Other Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Assets [Line Items]
Capitalized software purchases and direct costs associated with software developed for internal use	$ 700	$ 1,200
Accumulated amortization of capitalized software	37,700	37,600
Amortization expense of capitalized software	2,300	2,900	$ 3,200
Rabbi Trust
Other Assets [Line Items]
Assets held in Rabbi Trust	$ 25,489	$ 25,715