Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Leases Disclosure [Line Items]
Total rent expenses	$ 11,300	$ 10,500	$ 9,400
Accumulated depreciation on capital leases	640	530
Depreciation expense	130	140
Capital lease obligation, current	10
Property, Plant and Equipment, Other Types
Leases Disclosure [Line Items]
Leasehold Improvements on capital leases	$ 900	$ 940