Income Taxes - Summary of Expense (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current tax expense (benefit)
Federal									$ (446)	$ 5,650	$ 2,629
State									55	1,448	955
Current tax expense, Gross									(391)	7,098	3,584
Deferred tax expense (benefit)
Federal									345	3,050	967
State									(342)	665	208
Deferred tax expense (benefit), Gross									3	3,715	1,175
Income tax expense	$ (2,591)	$ (466)	$ 1,285	$ 1,384	$ 3,309	$ 3,996	$ 2,250	$ 1,258	$ (388)	$ 10,813	$ 4,759