Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Rental expense	$ 89,900,000	$ 92,700,000	$ 96,800,000
Future purchase commitments	76,000,000
Purchase commitment period	3 years
Allegations loss	$ 0