Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Aug. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Income Taxes Disclosure [Line Items]
Income tax liability paid	$ 6,000,000				$ 5,958,000
Interest and penalties paid	$ 1,500,000
(Benefit) provision for income taxes		$ 0	$ (448,000)	$ 0	(448,000)
Unrecognized tax benefits		0		0		$ 0
Receive a refund from tax return			$ 400,000		$ 400,000		$ 400,000	$ 700,000	$ 700,000
Federal [Member]
Income Taxes Disclosure [Line Items]
Receive a refund from tax return		$ 1,100,000		$ 1,100,000