Commitments & Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
Operating lease expiration period	2025-12
Rent expense	$ 13,516	$ 13,245	$ 12,479
Minimum rental payments under capital leases	458
Minimum rental payments under operating leases	25,624
Minimal rental payments under operating leases, net of sublease payments	1,149
Unconditional purchase obligations over next six years	$ 49,264
Minimum
Long-term Purchase Commitment [Line Items]
Operating lease term	1 year
Unconditional purchase obligations	1 year
Maximum
Long-term Purchase Commitment [Line Items]
Operating lease term	10 years
Unconditional purchase obligations	5 years
Reported Value Measurement
Long-term Purchase Commitment [Line Items]
Amount outstanding under letters of credit	$ 823	$ 1,030