Securities Available-for-Sale - Continuous Unrealized Loss Position for 12 Months or Less and 12 Months or Longer (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 140,208	$ 30,036
Less Than 12 Months, Unrealized Losses	445	67
12 Months or Longer, Fair Value	34,448	55,024
12 Months or Longer, Unrealized Losses	645	1,266
Total, Fair Value	174,656	85,060
Total, Unrealized Losses	1,090	1,333
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value		1,989
Less Than 12 Months, Unrealized Losses		10
Total, Fair Value		1,989
Total, Unrealized Losses		10
SBA Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	10,959	1,031
Less Than 12 Months, Unrealized Losses	24	2
12 Months or Longer, Fair Value	0
12 Months or Longer, Unrealized Losses	0
Total, Fair Value	10,959	1,031
Total, Unrealized Losses	24	2
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	127,281	26,519
Less Than 12 Months, Unrealized Losses	372	52
12 Months or Longer, Fair Value	27,894	49,341
12 Months or Longer, Unrealized Losses	116	248
Total, Fair Value	155,175	75,860
Total, Unrealized Losses	488	300
Privately Issued Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	415
Less Than 12 Months, Unrealized Losses	2
12 Months or Longer, Fair Value	467	490
12 Months or Longer, Unrealized Losses	15	13
Total, Fair Value	882	490
Total, Unrealized Losses	17	13
Obligations Issued by States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or Longer, Fair Value	4,298	3,820
12 Months or Longer, Unrealized Losses	403	878
Total, Fair Value	4,298	3,820
Total, Unrealized Losses	403	878
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	1,553	497
Less Than 12 Months, Unrealized Losses	47	3
12 Months or Longer, Fair Value	1,789	1,373
12 Months or Longer, Unrealized Losses	111	127
Total, Fair Value	3,342	1,870
Total, Unrealized Losses	$ 158	$ 130