Capital and Financing Transactions - Tabular Disclosure of the Effect of Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Disclosure [Abstract]
Amount of gain (loss) recognized in other comprehensive income on derivatives	$ (5,457)	$ 1,448	$ (9,882)	$ (6,426)
Net loss reclassified from accumulated other comprehensive loss into earnings	1,883	1,915	5,475	5,441
Amount of loss recognized in income on derivatives (ineffective portion, reclassifications of missed forecasted transactions and amounts excluded from effectiveness testing)	$ 623	$ 41	$ 1,868	$ 238