Derivative Instruments and Hedging Activities - Offsetting of Derivative Assets and Liabilities in the Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Derivative assets
Gross amounts of recognized assets	$ 12,354	$ 2,991
Gross amounts offset in the statement of financial position	2,022	0
Net amounts of assets presented in the statement of financial position	10,332	2,991
Gross amounts of financial instruments not offset in the statement of financial position	51	0
Net amount	10,383	2,991
Derivative liabilities
Gross amounts of recognized liabilities	14,714	40,259
Gross amounts offset in the statement of financial position	(2,022)	0
Net amounts of liabilities presented in the statement of financial position	12,692	40,259
Gross amounts of financial instruments not offset in the statement of financial position	0	757
Net amount	$ 12,692	$ 41,016