Lease Exit and Related Charges (Changes to Accrued Loss on Excess Office Facilities) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Changes To Accrued Loss On Excess Office Facilities [Abstract]
Lease exit and related charges	$ 2,100	$ 2,501	$ 880	$ 3,089
Percent reduction in office space	43.00%
Accrued Loss on Excess Office Facilities [Roll Forward]
Accrued loss, beginning of year		234	254	4,213
Additions and adjustments to the lease loss accrual, including sublease income estimate revision, and related asset write-downs		2,981	668	1,421
Less amounts paid, net of sublease income		(620)	(688)	(5,380)
Accrued loss, end of year		2,595	234	254
Less current portion (included in Accrued and other current liabilities)		(822)	(234)	(254)
Accrued loss, non-current portion (included in Other long term liabilities)		$ 1,773	$ 0	$ 0