Summary of Significant Accounting Policies - Summary of Operating Lease Exit Accruals (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Accounting Policies [Abstract]
Balance at December 31, 2014	$ 18,962
Lease exit expense	1,485	$ (272)
Payments	(4,671)
Balance at September 30, 2015	$ 15,776