Derivative Financial Instruments - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative interest expense	$ 0	$ 69	$ 0	$ 3,886
Income tax expense	10,292	21,274	46,275	76,842
Net income	(24,024)	(36,281)	(98,825)	(125,075)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative interest expense	0	69	0	3,886
Income tax expense	0	0	0	(1,469)
Net income	$ 0	$ 69	$ 0	$ 2,417