Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions		12 Months Ended
	Feb. 18, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Operating lease obligation expiration period		2022
Rental expense for operating leases		$ 13.6	$ 13.3	$ 13.3
Sublease income		0.9	0.9	$ 0.8
Estimated total costs to remediate property	$ 8.3
Accrual for reasonably estimable remediation cost		$ 7.1	$ 8.0