Quarterly report pursuant to Section 13 or 15(d)

Loans and Leases - Additional Information (Detail)

v3.7.0.1
Loans and Leases - Additional Information (Detail)
$ in Thousands
 3 Months Ended
Mar. 31, 2017
USD ($)
Property
Dec. 31, 2016
USD ($)
Property
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Accrued interest receivable $ 10,774 $ 10,987    
Loans and leases receivable $ 3,910,799 $ 3,812,340    
Number of real estate properties | Property 7 12    
Other real estate owned (OREO), net $ 4,636 $ 7,484    
TDR loans receivable $ 17,000 18,000    
Principal and interest due 3 months      
Reserves relating to loans included in allowance for loan losses $ 3,700 3,400    
PCI Loans and Leases [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loans and leases receivable 8,069 8,892 $ 14,190 $ 14,573
Central Bancorp, Inc [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Other real estate owned (OREO), net   $ 5,700    
Securities Pledged as Collateral [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loans and leases receivable 1,000,000      
Loans and Finance Receivables [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Accrued interest receivable $ 8,200