Derivative Instruments - (Details 2) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Offsetting Derivative Assets
Gross amounts recognized	$ 37	$ 446
Gross amounts offset in the consolidated balance sheets	0	0
Net amounts presented in the consolidated balance sheets	37	446
Financial instruments	37	282
Financial collateral pledged	0	0
Net amounts	0	164
Offsetting Derivative Liabilities
Gross amounts recognized	13,312	6,454
Gross amounts offset in the consolidated balance sheets	0	0
Net amounts presented in the consolidated balance sheets	13,312	6,454
Financial instruments	37	282
Financial collateral pledged	9,872	6,020
Net amounts	$ 3,403	$ 152