Restructuring - Activity in Restructuring Liability Accounts (Detail) - 2013 Restructuring [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 1,960
Provision-net	392
Usage	(476)
Ending Balance	1,876
Lease/Rental Terminations [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,786
Provision-net	(3)
Usage	(91)
Ending Balance	1,692
One-Time Employee Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	65
Provision-net	483
Usage	(364)
Ending Balance	184
Datacenter Consolidation, Other [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	109
Provision-net	(88)
Usage	$ (21)