Quarterly report pursuant to Section 13 or 15(d)

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

v3.5.0.2
Derivative Instruments and Hedging Activities Credit Risk - Counterparty Exposure (Details) - USD ($)
$ in Thousands
Jun. 30, 2016
Dec. 31, 2015
Offsetting Assets and Liabilities [Line Items]    
Derivative, Collateral, Obligation to Return Cash $ 4,500  
Derivative, Collateral, Right to Reclaim Cash 269,358  
Derivative Financial Instruments, Assets [Member]    
Offsetting Assets and Liabilities [Line Items]    
Derivative, Fair Value, Net 223,985 $ 271,509
Derivative Financial Instruments, Liabilities [Member]    
Offsetting Assets and Liabilities [Line Items]    
Derivative, Fair Value, Net $ (160,724) $ (7,285)