Securities - Securities Available for Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 493,691	$ 540,614
Unrealized Gains	7,683	12,411
Unrealized Losses	(5,539)	(6,982)
Fair Value	495,835	546,043
U.S. Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	139,823	141,300
Unrealized Gains	1,107	1,579
Unrealized Losses	(579)	(1,128)
Fair Value	140,351	141,751
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	153,492	165,828
Unrealized Gains	4,194	6,234
Unrealized Losses	(649)	(243)
Fair Value	157,037	171,819
Residential and Multi-Family Mortgage [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	136,807	160,316
Unrealized Gains	551	1,060
Unrealized Losses	(2,382)	(3,394)
Fair Value	134,976	157,982
Corporate Notes and Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,299	19,794
Unrealized Gains	77	165
Unrealized Losses	(962)	(1,271)
Fair Value	17,414	18,688
Pooled Trust Preferred [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	800	800
Unrealized Gains	1,249	2,613
Unrealized Losses	0	0
Fair Value	2,049	3,413
Pooled SBA [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	43,450	51,556
Unrealized Gains	505	760
Unrealized Losses	(918)	(907)
Fair Value	43,037	51,409
Other Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,020	1,020
Unrealized Gains	0	0
Unrealized Losses	(49)	(39)
Fair Value	$ 971	$ 981