| Assets and Liabilities Measured at Fair Value on Recurring Basis | 
As of December 31, 2017 and 2016, assets and liabilities measured at fair value on a recurring basis are as follows: 
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   | 
Level 1  | 
   | 
Level 2  | 
   | 
Level 3  | 
   | 
   | 
 
   | 
Quoted Prices in Active Markets for Identical Assets  | 
   | 
Significant Observable Inputs with No Active Market with Identical Characteristics  | 
   | 
Significant Unobservable Inputs  | 
   | 
Balance  | 
 
   | 
(In thousands)  | 
 
December 31, 2017  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Securities available for sale:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Mortgage-backed securities  | 
$  | 
—  | 
 
  | 
   | 
$  | 
303,609  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
303,609  | 
 
  | 
 
Collateralized mortgage obligations  | 
—  | 
 
  | 
   | 
117,768  | 
 
  | 
   | 
—  | 
 
  | 
   | 
117,768  | 
 
  | 
 
U.S. government agency securities  | 
—  | 
 
  | 
   | 
7,414  | 
 
  | 
   | 
—  | 
 
  | 
   | 
7,414  | 
 
  | 
 
Municipal bonds-tax exempt  | 
—  | 
 
  | 
   | 
127,475  | 
 
  | 
   | 
—  | 
 
  | 
   | 
127,475  | 
 
  | 
 
U.S. treasury securities  | 
152  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
152  | 
 
  | 
 
Mutual funds  | 
22,386  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
22,386  | 
 
  | 
 
Total securities available for sale  | 
$  | 
22,538  | 
 
  | 
 
  | 
$  | 
556,266  | 
 
  | 
 
  | 
$  | 
—  | 
 
  | 
 
  | 
$  | 
578,804  | 
 
  | 
 
December 31, 2016  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Securities available for sale:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Mortgage-backed securities  | 
$  | 
—  | 
 
  | 
   | 
$  | 
229,630  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
229,630  | 
 
  | 
 
Collateralized mortgage obligations  | 
—  | 
 
  | 
   | 
76,451  | 
 
  | 
   | 
—  | 
 
  | 
   | 
76,451  | 
 
  | 
 
U.S. government agency securities  | 
—  | 
 
  | 
   | 
7,441  | 
 
  | 
   | 
—  | 
 
  | 
   | 
7,441  | 
 
  | 
 
SBA loan pools securities  | 
—  | 
 
  | 
   | 
4,146  | 
 
  | 
   | 
—  | 
 
  | 
   | 
4,146  | 
 
  | 
 
Municipal bonds-tax exempt  | 
—  | 
 
  | 
   | 
158,030  | 
 
  | 
   | 
—  | 
 
  | 
   | 
158,030  | 
 
  | 
 
Municipal bonds-taxable  | 
—  | 
 
  | 
   | 
13,701  | 
 
  | 
   | 
—  | 
 
  | 
   | 
13,701  | 
 
  | 
 
Corporate bonds  | 
—  | 
 
  | 
   | 
5,015  | 
 
  | 
   | 
—  | 
 
  | 
   | 
5,015  | 
 
  | 
 
U.S. treasury securities  | 
156  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
156  | 
 
  | 
 
Mutual funds  | 
22,394  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
22,394  | 
 
  | 
 
Total securities available for sale  | 
$  | 
22,550  | 
 
  | 
   | 
$  | 
494,414  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
516,964  | 
 
  | 
 
  
  
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| Assets and Liabilities Measured at Fair Value on Non-Recurring Basis | 
As of December 31, 2017 and 2016, assets and liabilities measured at fair value on a non-recurring basis are as follows:
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   | 
Level 1  | 
   | 
Level 2  | 
   | 
Level 3  | 
   | 
   | 
 
   | 
Quoted Prices in Active Markets for Identical Assets  | 
   | 
Significant Observable Inputs With No Active Market With Identical Characteristics  | 
   | 
Significant Unobservable Inputs  | 
   | 
Loss During the Years Ended  | 
 
   | 
(In thousands)  | 
 
December 31, 2017  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Impaired loans (excluding PCI loans) (1)
  | 
$  | 
—  | 
 
  | 
   | 
$  | 
6,121  | 
 
  | 
   | 
$  | 
2,436  | 
 
  | 
   | 
$  | 
2,730  | 
 
  | 
 
OREO (2)
  | 
—  | 
 
  | 
   | 
1,946  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
December 31, 2016  | 
   | 
   | 
   | 
 
Assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Impaired loans (3)
  | 
$  | 
—  | 
 
  | 
   | 
$  | 
15,257  | 
 
  | 
   | 
$  | 
6,767  | 
 
  | 
   | 
$  | 
868  | 
 
  | 
 
OREO (4)
  | 
—  | 
 
  | 
   | 
7,484  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
  
 
 
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(1)   | 
Includes real estate loans of $6.7 million, and commercial and industrial loans of $1.7 million.
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(2)   | 
Includes properties from the foreclosure of commercial property loans of $237 thousand and residential property loans of $1.7 million.
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(3)   | 
Includes real estate loans of $17.8 million, commercial and industrial loans of $3.8 million, and consumer loans of $419 thousand. 
  | 
 
 
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(4)   | 
Includes properties from the foreclosure of commercial property loans of $5.4 million and residential property loans of $2.1 million.
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| Estimated Fair Values of Financial Instruments | 
The estimated fair values of financial instruments were as follows:
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   | 
December 31, 2017  | 
 
   | 
Carrying Amount  | 
   | 
Fair Value  | 
 
   | 
Level 1  | 
   | 
Level 2  | 
   | 
Level 3  | 
 
   | 
(In thousands)  | 
 
Financial assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Cash and due from banks  | 
$  | 
153,826  | 
 
  | 
   | 
$  | 
153,826  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
 
Securities available for sale  | 
578,804  | 
 
  | 
   | 
22,538  | 
 
  | 
   | 
556,266  | 
 
  | 
   | 
—  | 
 
  | 
 
Loans and leases receivable, net of allowance for loan and lease losses  | 
4,273,415  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
4,213,689  | 
 
  | 
 
Loans held for sale  | 
6,394  | 
 
  | 
   | 
—  | 
 
  | 
   | 
6,394  | 
 
  | 
   | 
—  | 
 
  | 
 
Accrued interest receivable  | 
12,770  | 
 
  | 
   | 
12,770  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
FHLB stock  | 
16,385  | 
 
  | 
   | 
—  | 
 
  | 
   | 
16,385  | 
 
  | 
   | 
—  | 
 
  | 
 
Financial liabilities:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Noninterest-bearing deposits  | 
1,312,274  | 
 
  | 
   | 
—  | 
 
  | 
   | 
1,312,274  | 
 
  | 
   | 
—  | 
 
  | 
 
Interest-bearing deposits  | 
3,036,380  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
2,973,139  | 
 
  | 
 
Borrowings  | 
267,270  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
267,270  | 
 
  | 
 
Accrued interest payable  | 
5,309  | 
 
  | 
   | 
5,309  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
Off-balance sheet items:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Commitments to extend credit  | 
318,634  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
318,634  | 
 
  | 
 
Standby letters of credit  | 
19,294  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
19,294  | 
 
  | 
 
Commercial letters of credit  | 
9,308  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
9,308  | 
 
  | 
 
  
 
  
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   | 
December 31, 2016  | 
 
   | 
Carrying Amount  | 
   | 
Fair Value  | 
 
   | 
Level 1  | 
   | 
Level 2  | 
   | 
Level 3  | 
 
   | 
(In thousands)  | 
 
Financial assets:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Cash and due from banks  | 
$  | 
147,235  | 
 
  | 
   | 
$  | 
147,235  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
 
Securities available for sale  | 
516,964  | 
 
  | 
   | 
22,550  | 
 
  | 
   | 
494,414  | 
 
  | 
   | 
—  | 
 
  | 
 
Loans receivable, net of allowance for loan losses  | 
3,812,340  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
3,789,579  | 
 
  | 
 
Loans held for sale  | 
9,316  | 
 
  | 
   | 
—  | 
 
  | 
   | 
9,316  | 
 
  | 
   | 
—  | 
 
  | 
 
Accrued interest receivable  | 
10,987  | 
 
  | 
   | 
10,987  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
FHLB stock  | 
16,385  | 
 
  | 
   | 
—  | 
 
  | 
   | 
16,385  | 
 
  | 
   | 
—  | 
 
  | 
 
Financial liabilities:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Noninterest-bearing deposits  | 
1,203,240  | 
 
  | 
   | 
—  | 
 
  | 
   | 
1,203,240  | 
 
  | 
   | 
—  | 
 
  | 
 
Interest-bearing deposits  | 
2,606,497  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
2,541,929  | 
 
  | 
 
Borrowings  | 
333,978  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
333,978  | 
 
  | 
 
Accrued interest payable  | 
2,567  | 
 
  | 
   | 
2,567  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
Off-balance sheet items:  | 
   | 
   | 
   | 
   | 
   | 
   | 
   | 
 
Commitments to extend credit  | 
310,987  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
310,987  | 
 
  | 
 
Standby letters of credit  | 
15,669  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
15,669  | 
 
  | 
 
Commercial letters of credit  | 
4,215  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
4,215  | 
 
  | 
 
  
 
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