Summary of Significant Accounting Policies - New Accounting Standards and Interpretations (Details) - Accounting Standards Update 2015-03 $ in Thousands	Dec. 31, 2016 USD ($)
Senior Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ 3,300
Repurchase Agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	1,300
Secured Debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	189
Other Noncurrent Assets | Senior Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	(3,300)
Other Noncurrent Assets | Repurchase Agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	(1,300)
Other Noncurrent Assets | Secured Debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ (189)