Long-Term Debt - Schedule of Interest Expense Related To Debt (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Debt Disclosure [Abstract]
Interest expense	$ 9,145	$ 9,038	$ 18,111	$ 18,871
Amortization of debt issuance costs related to long-term debt, including our credit facility	830	827	1,673	1,653
Capitalized interest	0	47	0	47
Commitment fees	$ 774	$ 831	$ 1,561	$ 1,780
Commitment fee (basis points)			0.30%