Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Income Taxes [Line Items]
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.
Current deferred tax assets, net	$ 26,900	$ 31,700
Long-term deferred tax liabilities, net	186,642	$ 203,476
Foreign Tax Authority [Member] | Alberta [Member]
Income Taxes [Line Items]
Income tax expense, cumulative revaluation of certain deferred tax liabilities	$ 2,600