Office Closing and Termination Costs - Summary of Termination Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Termination costs			$ 1,414		$ 5,372
Building lease			3,232		0
Stock-based compensation expense			1,721		2,999
Total termination costs	$ 417	$ 0	$ 6,367	$ 0	$ 8,371