Derivative Instruments and Hedging Activities - Offsetting Assets and Liabilities in the Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivative assets
Gross amounts of recognized assets	$ 2,991	$ 0
Gross amounts offset in the statement of financial position	0	0
Net amounts of assets presented in the statement of financial position	2,991	0
Gross amounts of financial instruments not offset in the statement of financial position	0	0
Net amount	2,991	0
Derivative liabilities
Gross amounts of recognized liabilities	40,259	0
Gross amounts offset in the statement of financial position	0	0
Net amounts of liabilities presented in the statement of financial position	40,259	0
Gross amounts of financial instruments not offset in the statement of financial position	757	0
Net amount	$ 41,016	$ 0