Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 6,395,000	$ 4,743,000	$ 11,867,000	$ 9,254,000
Payment of withholding taxes to foreign tax authorities	4,800,000	3,800,000	9,800,000	7,600,000
Deferred Tax Assets, Gross	193,700,000		193,700,000
Unrecognized tax benefits	19,800,000		19,800,000		18,800,000
Unrecognized tax benefits, reduction of long-term deferred tax assets	17,900,000		17,900,000		12,600,000
Unrecognized tax benefits included in long-term income taxes payable	1,900,000		1,900,000		6,200,000
Portion of unrecognized tax benefits, which if recognized, would be recorded as an income tax benefit	$ 1,900,000		$ 1,900,000