Derivatives Derivative Effect on Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Reclassification adjustment for cash flow hedges (including de-designated hedges)	$ 6,788	$ 13,989	$ 14,448
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	2,577
Dedesignated cash flow hedge amortization	6,788	5,193	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	8,796	14,448
Scenario, Forecast [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months				$ 3,460