Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Credit Risk - Counterparty Exposure (Details)

v3.7.0.1
Derivative Instruments and Hedging Activities Credit Risk - Counterparty Exposure (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Dec. 31, 2016
Offsetting Assets and Liabilities [Line Items]    
Derivative, Collateral, Obligation to Return Cash $ 4,323  
Derivative, Collateral, Right to Reclaim Cash 220,190  
Derivative Financial Instruments, Assets [Member]    
Offsetting Assets and Liabilities [Line Items]    
Derivative, Fair Value, Net 253,564 $ 324,182
Derivative Financial Instruments, Liabilities [Member]    
Offsetting Assets and Liabilities [Line Items]    
Derivative, Fair Value, Net $ (20,363) $ (12,501)