Recent and Pending Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncement, Early Adoption [Line Items]
Reclassifications from operating activities		$ (37,461)	$ (41,837)	$ (41,559)
Reclassifications to financing activities		$ (16,723)	$ (32,809)	$ (15,151)
Adjustments for new accounting principle, early adoption
New Accounting Pronouncement, Early Adoption [Line Items]
Reclassifications from operating activities	$ 3,800
Accounting Standards Update 2016-09 | Adjustments for new accounting principle, early adoption
New Accounting Pronouncement, Early Adoption [Line Items]
Reclassifications to financing activities	$ 3,800