Office Closing and Termination Costs - Exit Costs Included in Accrued Liabilities in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Exit costs included in accrued liabilities in consolidated balance sheet
Beginning balance at December 31, 2016	$ 2,460
Accrued severance costs	2,422	$ 0
Accrued building rent	28
Payments	(437)
Ending balance at March 31, 2017	$ 4,473