Summary of Significant Accounting Policies - reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Reclassifications to financial statements
Other revenues	$ 1,190	$ 1,747
Other expense	100	375
Deferred financing costs, net of amortization	$ 36,147		$ 38,336
Reclassification Adjustment
Reclassifications to financial statements
Other revenues		2,700
Other expense		$ 1,700
Accounting Standards Update 2015-03 | Secured financing agreements | Reclassification Adjustment
Reclassifications to financial statements
Deferred financing costs, net of amortization			38,300
Accounting Standards Update 2015-03 | Convertible Senior Notes | Reclassification Adjustment
Reclassifications to financial statements
Deferred financing costs, net of amortization			$ 1,400