Gross Unrealized Losses and Fair Value by Length of Time of Available-For-Sale Securities (Detail) (Available-for-Sale Securities, USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Number of securities	58	7
Fair Value	$ 321,936	$ 46,404
Less than 12 months	15,243	231
More than 12 months	415	236
Total Unrealized Losses	15,658	467
U.S. Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Number of securities	15	2
Fair Value	139,466	29,900
Less than 12 months	8,222	98
More than 12 months	0	0
Total Unrealized Losses	8,222	98
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Number of securities	12	1
Fair Value	11,680	390
Less than 12 months	156	1
More than 12 months	0	0
Total Unrealized Losses	156	1
Mortgage-Backed
Schedule of Available-for-sale Securities [Line Items]
Number of securities	30	2
Fair Value	169,377	12,653
Less than 12 months	6,865	128
More than 12 months	127	0
Total Unrealized Losses	6,992	128
Trust Preferred
Schedule of Available-for-sale Securities [Line Items]
Number of securities	1	1
Fair Value	1,413	1,465
Less than 12 months	0	0
More than 12 months	288	236
Total Unrealized Losses	288	236
Corporate Debt
Schedule of Available-for-sale Securities [Line Items]
Number of securities		1
Fair Value		1,996
Less than 12 months		4
More than 12 months		0
Total Unrealized Losses		$ 4