Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 30,019,000	$ 29,435,000	$ 88,160,000	$ 82,003,000
Effective tax rate	26.40%	29.60%	26.60%	27.70%
Foreign withholding taxes		$ 5,200,000
Minimum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible change in unrecognized tax benefits over next 12 months	$ 0		$ 0
Maximum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible change in unrecognized tax benefits over next 12 months	$ 1,400,000		$ 1,400,000