Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Unlimited range of net operating loss carryforwards	5 years
Cash payments for income taxes, including interest	$ 81,600,000	$ 65,400,000	$ 78,500,000
Liability for unrecognized tax benefits	6,684,000	4,648,000	12,303,000
Unrecognized tax benefits highly certain	4,100,000	3,400,000
Unrecognized tax benefits that would impact effective tax rate	2,000,000	1,000,000
Accrued interest	300,000	100,000
Interest expense (income)	100,000	(400,000)
Penalties accrued	$ 0	$ 0