Office Closing and Exit Costs - Summary of Termination Costs (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	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Additional accruals for severance costs						$ 11,706	$ 5,372
Building lease						3,147	0
Stock-based compensation expense (gain)						217	2,999
Total termination costs	$ 8,780	$ (77)	$ 417	$ 5,950	$ 8,371	$ 15,070	$ 8,371	$ 0