Investment Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail) (USD $) In Thousands, unless otherwise specified
|
Jun. 30, 2014
Security
|
Dec. 31, 2013
Security
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
$ 583
|
$ 10,607
|
Available-for-Sale Within One Year, Estimated Fair Value |
88,837
|
366,638
|
Available-for-Sale Within One Year, Number of Securities |
21
|
124
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
6,560
|
8,362
|
Available-for-Sale More than One Year, Estimated Fair Value |
193,617
|
107,384
|
Available-for-Sale More than One Year, Number of Securities |
78
|
45
|
Available-for-Sale, Gross Unrealized Loss |
7,143
|
18,969
|
Available-for-Sale, Estimated Fair Value |
282,454
|
474,022
|
Available-for-Sale, Number of Securities |
99
|
169
|
Municipal bonds-taxable [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
787
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
22,817
|
Available-for-Sale Within One Year, Number of Securities |
|
16
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
145
|
293
|
Available-for-Sale More than One Year, Estimated Fair Value |
6,996
|
3,813
|
Available-for-Sale More than One Year, Number of Securities |
7
|
4
|
Available-for-Sale, Gross Unrealized Loss |
145
|
1,080
|
Available-for-Sale, Estimated Fair Value |
6,996
|
26,630
|
Available-for-Sale, Number of Securities |
7
|
20
|
Municipal bonds-tax exempt [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
30
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
8,562
|
Available-for-Sale Within One Year, Number of Securities |
|
5
|
Available-for-Sale More than One Year, Number of Securities |
|
|
Available-for-Sale, Gross Unrealized Loss |
0
|
30
|
Available-for-Sale, Estimated Fair Value |
|
8,562
|
Available-for-Sale, Number of Securities |
|
5
|
U.S. treasury bills [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
1
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
19,996
|
Available-for-Sale Within One Year, Number of Securities |
|
2
|
Available-for-Sale More than One Year, Number of Securities |
|
|
Available-for-Sale, Gross Unrealized Loss |
|
1
|
Available-for-Sale, Estimated Fair Value |
|
19,996
|
Available-for-Sale, Number of Securities |
|
2
|
Collateralized mortgage obligations [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
363
|
2,353
|
Available-for-Sale Within One Year, Estimated Fair Value |
67,236
|
87,026
|
Available-for-Sale Within One Year, Number of Securities |
16
|
27
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
674
|
864
|
Available-for-Sale More than One Year, Estimated Fair Value |
19,818
|
14,657
|
Available-for-Sale More than One Year, Number of Securities |
9
|
7
|
Available-for-Sale, Gross Unrealized Loss |
1,037
|
3,217
|
Available-for-Sale, Estimated Fair Value |
87,054
|
101,683
|
Available-for-Sale, Number of Securities |
25
|
34
|
Mortgage-backed securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
220
|
3,437
|
Available-for-Sale Within One Year, Estimated Fair Value |
21,601
|
170,324
|
Available-for-Sale Within One Year, Number of Securities |
5
|
51
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
1,790
|
2,589
|
Available-for-Sale More than One Year, Estimated Fair Value |
68,558
|
30,947
|
Available-for-Sale More than One Year, Number of Securities |
24
|
12
|
Available-for-Sale, Gross Unrealized Loss |
2,010
|
6,026
|
Available-for-Sale, Estimated Fair Value |
90,159
|
201,271
|
Available-for-Sale, Number of Securities |
29
|
63
|
U.S. government agency securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
3,942
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
50,932
|
Available-for-Sale Within One Year, Number of Securities |
|
19
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
3,096
|
3,374
|
Available-for-Sale More than One Year, Estimated Fair Value |
74,864
|
32,606
|
Available-for-Sale More than One Year, Number of Securities |
27
|
12
|
Available-for-Sale, Gross Unrealized Loss |
3,096
|
7,316
|
Available-for-Sale, Estimated Fair Value |
74,864
|
83,538
|
Available-for-Sale, Number of Securities |
27
|
31
|
Corporate bonds [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
9
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
5,024
|
Available-for-Sale Within One Year, Number of Securities |
|
1
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
103
|
177
|
Available-for-Sale More than One Year, Estimated Fair Value |
7,885
|
11,803
|
Available-for-Sale More than One Year, Number of Securities |
2
|
3
|
Available-for-Sale, Gross Unrealized Loss |
103
|
186
|
Available-for-Sale, Estimated Fair Value |
7,885
|
16,827
|
Available-for-Sale, Number of Securities |
2
|
4
|
SBA loan pool securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Number of Securities |
|
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
661
|
969
|
Available-for-Sale More than One Year, Estimated Fair Value |
12,561
|
12,629
|
Available-for-Sale More than One Year, Number of Securities |
4
|
4
|
Available-for-Sale, Gross Unrealized Loss |
661
|
969
|
Available-for-Sale, Estimated Fair Value |
12,561
|
12,629
|
Available-for-Sale, Number of Securities |
4
|
4
|
Other securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
48
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
1,957
|
Available-for-Sale Within One Year, Number of Securities |
|
3
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
91
|
96
|
Available-for-Sale More than One Year, Estimated Fair Value |
2,935
|
929
|
Available-for-Sale More than One Year, Number of Securities |
5
|
3
|
Available-for-Sale, Gross Unrealized Loss |
91
|
144
|
Available-for-Sale, Estimated Fair Value |
$ 2,935
|
$ 2,886
|
Available-for-Sale, Number of Securities |
5
|
6
|