Income Taxes - Components of Income Tax Expense (Benefit) Attributable to Current Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income before income tax expense (benefit)	$ 27,327	$ 45,339	$ 46,063
Federal tax	753	575	(144)
State tax	1,087	958	1,179
Foreign tax	2	0	4
Current income tax benefit	1,842	1,533	1,039
Federal tax	6,046	16,790	18,378
State tax	(1,249)	(355)	296
Foreign tax	(57)	(159)	(634)
Deferred income tax benefit	4,740	16,276	18,040
Total income tax expense (benefit)	$ 6,582	$ 17,809	$ 19,079