Debt and Financing Arrangements - Line of Credit Facility (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 05, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Long-term debt		$ 370,313
Working capital facility | Wells Fargo, National Association
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 30,000
Commitment fee (as a percent)	0.35%
Debt interest expense		$ 300	$ 300	$ 300
LIBOR | Working capital facility | Wells Fargo, National Association
Line of Credit Facility [Line Items]
Variable rate of interest	2.50%