Derivative Instruments - (Details 2) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Offsetting Derivative Assets
Gross amounts recognized	$ 1,357	$ 4,778
Gross amounts offset in the Consolidated Balance Sheets	0	0
Net amounts presented in the Consolidated Balance Sheets	1,357	4,778
Financial instruments	759	567
Financial collateral pledged	0	0
Net amounts	598	4,211
Gross amounts not offset in the Consolidated Balance Sheets
Gross amounts recognized	5,327	4,893
Gross amounts offset in the Consolidated Balance Sheets	0	0
Net amounts presented in the Consolidated Balance Sheets	5,327	4,893
Financial instruments	759	567
Financial collateral pledged	4,568	4,326
Net amounts	$ 0	$ 0

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