Derivative Instruments and Hedging Activities (Details) - Cash Flow Hedges - Cash Flow Hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding	$ 1,220,000	$ 650,000
Derivative asset fair value	4,787	1,166
Derivative liability fair value	$ (8,950)	$ (3,096)
Weighted-average interest rate received	1.24%	1.63%
Weighted-average interest rate paid	0.75%	0.16%
Weighted-average maturity (in years)	3 years 10 months 28 days	4 years 6 months 8 days