Balance Sheet Account Detail - Prepaid Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid operating expenses	$ 3,930	$ 3,507
Current portion of debt issuance costs	0	0
Prepaid expenses and other assets	3,930	3,507
Accounting Standards Update 2015-03 [Member] | Long-term Debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	1,300	2,200
Accounting Standards Update 2015-03 [Member] | Prepaid Expenses and Other Current Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ (1,300)	$ (2,200)