Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Interest Spread on Interest Rate Swaps (Details)

v3.7.0.1
Derivative Instruments and Hedging Activities Interest Spread on Interest Rate Swaps (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative, Average Notional Amount $ 16,574,247 $ 22,574,979
Interest Rate Swap [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Interest Expense on Interest Rate Swap and Swaption Agreements 7,904 6,190
Derivative, Average Notional Amount $ 18,707,666 $ 14,954,600