Investment Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail) (USD $) In Thousands, unless otherwise specified
|
Mar. 31, 2014
Security
|
Dec. 31, 2013
Security
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
$ 1,411
|
$ 10,607
|
Available-for-Sale Within One Year, Estimated Fair Value |
171,377
|
366,638
|
Available-for-Sale Within One Year, Number of Securities |
46
|
124
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
10,559
|
8,362
|
Available-for-Sale More than One Year, Estimated Fair Value |
215,948
|
107,384
|
Available-for-Sale More than One Year, Number of Securities |
89
|
45
|
Available-for-Sale, Gross Unrealized Loss |
11,970
|
18,969
|
Available-for-Sale, Estimated Fair Value |
387,325
|
474,022
|
Available-for-Sale, Number of Securities |
135
|
169
|
Collateralized mortgage obligations [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
519
|
2,353
|
Available-for-Sale Within One Year, Estimated Fair Value |
65,206
|
87,026
|
Available-for-Sale Within One Year, Number of Securities |
15
|
27
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
842
|
864
|
Available-for-Sale More than One Year, Estimated Fair Value |
20,383
|
14,657
|
Available-for-Sale More than One Year, Number of Securities |
9
|
7
|
Available-for-Sale, Gross Unrealized Loss |
1,361
|
3,217
|
Available-for-Sale, Estimated Fair Value |
85,589
|
101,683
|
Available-for-Sale, Number of Securities |
24
|
34
|
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, Gross Unrealized Loss |
|
|
Available-for-Sale More than One Year, Estimated Fair Value |
|
|
Available-for-Sale More than One Year, Number of Securities |
|
|
Available-for-Sale, Gross Unrealized Loss |
|
30
|
Available-for-Sale, Estimated Fair Value |
|
8,562
|
Available-for-Sale, Number of Securities |
|
5
|
Municipal bonds-taxable [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
3
|
787
|
Available-for-Sale Within One Year, Estimated Fair Value |
1,744
|
22,817
|
Available-for-Sale Within One Year, Number of Securities |
1
|
16
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
518
|
293
|
Available-for-Sale More than One Year, Estimated Fair Value |
12,907
|
3,813
|
Available-for-Sale More than One Year, Number of Securities |
11
|
4
|
Available-for-Sale, Gross Unrealized Loss |
521
|
1,080
|
Available-for-Sale, Estimated Fair Value |
14,651
|
26,630
|
Available-for-Sale, Number of Securities |
12
|
20
|
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, Gross Unrealized Loss |
|
|
Available-for-Sale More than One Year, Estimated Fair Value |
|
|
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
|
Mortgage-backed securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
889
|
3,437
|
Available-for-Sale Within One Year, Estimated Fair Value |
104,423
|
170,324
|
Available-for-Sale Within One Year, Number of Securities |
29
|
51
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
3,195
|
2,589
|
Available-for-Sale More than One Year, Estimated Fair Value |
74,226
|
30,947
|
Available-for-Sale More than One Year, Number of Securities |
27
|
12
|
Available-for-Sale, Gross Unrealized Loss |
4,084
|
6,026
|
Available-for-Sale, Estimated Fair Value |
178,649
|
201,271
|
Available-for-Sale, Number of Securities |
56
|
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 |
4,880
|
3,374
|
Available-for-Sale More than One Year, Estimated Fair Value |
80,979
|
32,606
|
Available-for-Sale More than One Year, Number of Securities |
30
|
12
|
Available-for-Sale, Gross Unrealized Loss |
4,880
|
7,316
|
Available-for-Sale, Estimated Fair Value |
80,979
|
83,538
|
Available-for-Sale, Number of Securities |
30
|
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 |
128
|
177
|
Available-for-Sale More than One Year, Estimated Fair Value |
11,856
|
11,803
|
Available-for-Sale More than One Year, Number of Securities |
3
|
3
|
Available-for-Sale, Gross Unrealized Loss |
128
|
186
|
Available-for-Sale, Estimated Fair Value |
11,856
|
16,827
|
Available-for-Sale, Number of Securities |
3
|
4
|
SBA loan pool securities [Member]
|
|
|
Summary of Investment Holdings [Line Items] |
|
|
Available-for-Sale Within One Year, Gross Unrealized Loss |
|
|
Available-for-Sale Within One Year, Estimated Fair Value |
|
|
Available-for-Sale Within One Year, Number of Securities |
|
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
867
|
969
|
Available-for-Sale More than One Year, Estimated Fair Value |
12,701
|
12,629
|
Available-for-Sale More than One Year, Number of Securities |
4
|
4
|
Available-for-Sale, Gross Unrealized Loss |
867
|
969
|
Available-for-Sale, Estimated Fair Value |
12,701
|
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 |
4
|
1,957
|
Available-for-Sale Within One Year, Number of Securities |
1
|
3
|
Available-for-Sale More than One Year, Gross Unrealized Loss |
129
|
96
|
Available-for-Sale More than One Year, Estimated Fair Value |
2,896
|
929
|
Available-for-Sale More than One Year, Number of Securities |
5
|
3
|
Available-for-Sale, Gross Unrealized Loss |
129
|
144
|
Available-for-Sale, Estimated Fair Value |
$ 2,900
|
$ 2,886
|
Available-for-Sale, Number of Securities |
6
|
6
|