Derivatives (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative assets, fair value		$ 28,534		$ 7,835
Derivative assets, aggregate notional amount		2,670,000		460,000
Derivative liabilities, fair value		(6,922)		(41,205)
Derivative liabilities, aggregate notional amount		1,210,000		9,220,000
Interest Rate Swap
Derivative [Line Items]
Derivative assets, fair value		28,534		7,835
Derivative assets, aggregate notional amount		2,670,000		460,000
Derivative liabilities, fair value		(6,922)		(12,108)
Derivative liabilities, aggregate notional amount		1,210,000		2,920,000
ERROR in label resolution.
Derivative [Line Items]
Derivative assets, fair value		0		0
Derivative assets, aggregate notional amount		0	[1]	0
Derivative liabilities, fair value		0		(29,097)
Derivative liabilities, aggregate notional amount	[1]	0		6,300,000
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
(Loss) gain on derivative instruments, net		(5,606)		(43,128)	$ (53,393)
Not Designated as Hedging Instrument [Member] | ERROR in label resolution.
Derivative [Line Items]
(Loss) gain on derivative instruments, net		(4,815)		(20,963)	(27,551)
Not Designated as Hedging Instrument [Member] | Receive-fixed interest rate swap | Interest Rate Swap
Derivative [Line Items]
(Loss) gain on derivative instruments, net		2,515		6,522	4,912
Not Designated as Hedging Instrument [Member] | Pay-fixed interest rate swap | Interest Rate Swap
Derivative [Line Items]
(Loss) gain on derivative instruments, net		$ (3,306)		$ (28,687)	$ (30,754)

[1] The Eurodollar futures aggregate notional amount represents the total notional of the 3-month contracts with expiration dates from 2017 to 2020. The maximum notional outstanding for any future 3-month period did not exceed $725,000 as of December 31, 2015.