Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Quarterly provision for income taxes, description	In determining the quarterly provision for income taxes, management uses an estimated annual effective tax rate based on forecasted annual pre-tax income, permanent tax differences, statutory tax rates and tax planning opportunities in the various jurisdictions in which the Company operates. The effect of significant discrete items is separately recognized in the quarter(s) in which they occur.
Long-term deferred tax liabilities	$ 274,465
Current deferred tax assets, net		$ 11,800
Long-term deferred tax liabilities, net		178,355
Accrued income and other taxes payable, current	$ 19,800	$ 40,300