Income Taxes - A Reconciliation of the Provision for income taxes from continuing operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Expected provision at federal statutory rate									$ 15,651	$ 13,446	$ 9,116
State income taxes, net									1,672	1,714	709
Change in valuation allowance									(718)	(2,385)	(7,618)
Domestic production activity deduction									(1,247)	(1,002)	0
Share based compensation									(1,408)
Federal and state tax credits									(1,065)	0	0
Other									648	454	58
Total	$ 3,775	$ 2,316	$ 3,570	$ 3,872	$ 3,527	$ 1,042	$ 4,599	$ 3,059	$ 13,533	$ 12,227	$ 2,265
Effective tax rate									30.30%	31.80%	8.70%