Equipment and Leasehold Improvements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 4.2	$ 3.0	$ 3.4
Assets Held under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Assets acquired under capital leases	2.7	1.7	3.0
Depreciation expense on capital lease assets	$ 2.2	$ 1.7	$ 2.2