Securities Available for Sale - Schedule of Investments Gross Unrealized Losses and Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014 Security	Dec. 31, 2013 Security
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities	5	120
Less than 12 Months, Fair Value	$ 6,894	$ 287,837
Less than 12 Months, Unrealized losses	43	9,605
12 Months or more, # of Securities	67	21
12 Months or more, Fair Value	191,411	70,886
12 Months or more, Unrealized losses	9,919	8,924
Total, # of Securities	72	141
Total, Fair Value	198,305	358,723
Total, Unrealized losses	9,962	18,529
Trust Preferred Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities
Less than 12 Months, Fair Value
Less than 12 Months, Unrealized losses
12 Months or more, # of Securities	8	8
12 Months or more, Fair Value	37,055	37,016
12 Months or more, Unrealized losses	6,876	6,908
Total, # of Securities	8	8
Total, Fair Value	37,055	37,016
Total, Unrealized losses	6,876	6,908
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities	4	44
Less than 12 Months, Fair Value	3,742	37,243
Less than 12 Months, Unrealized losses	27	3,129
12 Months or more, # of Securities	18	6
12 Months or more, Fair Value	15,850	5,518
12 Months or more, Unrealized losses	656	1,020
Total, # of Securities	22	50
Total, Fair Value	19,592	42,761
Total, Unrealized losses	683	4,149
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities		6
Less than 12 Months, Fair Value		20,869
Less than 12 Months, Unrealized losses		109
12 Months or more, # of Securities		3
12 Months or more, Fair Value		11,474
12 Months or more, Unrealized losses		252
Total, # of Securities		9
Total, Fair Value		32,343
Total, Unrealized losses		361
U.S. Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities	1	69
Less than 12 Months, Fair Value	3,152	229,223
Less than 12 Months, Unrealized losses	16	6,363
12 Months or more, # of Securities	41	4
12 Months or more, Fair Value	138,506	16,878
12 Months or more, Unrealized losses	2,387	744
Total, # of Securities	42	73
Total, Fair Value	141,658	246,101
Total, Unrealized losses	2,403	7,107
Private Label [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities		1
Less than 12 Months, Fair Value		502
Less than 12 Months, Unrealized losses		4
12 Months or more, # of Securities
12 Months or more, Fair Value
12 Months or more, Unrealized losses
Total, # of Securities		1
Total, Fair Value		502
Total, Unrealized losses		4
Subtotal Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, # of Securities		70
Less than 12 Months, Fair Value		229,725
Less than 12 Months, Unrealized losses		6,367
12 Months or more, # of Securities		4
12 Months or more, Fair Value		16,878
12 Months or more, Unrealized losses		744
Total, # of Securities		74
Total, Fair Value		246,603
Total, Unrealized losses		$ 7,111