Financial Derivatives - Hedging Description (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (16,400)	$ (22,800)	$ (19,700)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	2,000	1,200	200
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	1,500
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net of Tax	1,000
Gain (Loss) on Discontinuation of Interest Rate Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 0	$ 0	$ 0