Securities - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) Securities	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) Securities	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities holdings | Securities	0		0		0
Shareholders' equity percentage	10.00%		10.00%		10.00%
Proceeds from sale of securities	$ 4,420	$ 15,580	$ 4,420	$ 48,529
Securities	$ 365,867		365,867		$ 312,669
Pooled Trust Preferred [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of structured pooled trust preferred securities sold | Securities	2
Amortized cost of securities	$ 1,983		1,983
Proceeds from sale of securities	$ 922		$ 922