Debt - Components of Debt (Details) - USD ($) $ in Thousands	3 Months Ended		15 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017
Components of beginning debt balance [Abstract]
Long term debt, current portion, net of deferred issuance cost at beginning of period	$ 8,410
Long term debt, net of deferred issuance cost at beginning of period	245,731
Debt Borrowing, Repayment, Amortization during period [Abstract]
Repayment of debt and revolving credit facility	(40,000)	$ (20,000)
Amortization of deferred issuance cost	397	$ 397
Components of ending debt balance [Abstract]
Long term debt, current portion, net of deferred issuance cost at end of period	8,410		$ 8,410
Long term debt, net of deferred issuance cost at end of period	206,128		206,128
Wells Fargo Bank, National Association
Components of beginning debt balance [Abstract]
Debt under credit facilities at beginning of period	260,500
Deferred issuance cost, net at beginning of period	(6,359)
Total Debt, net of deferred issuance cost at beginning of period	254,141
Long term debt, current portion, net of deferred issuance cost at beginning of period	8,410
Long term debt, net of deferred issuance cost at beginning of period	245,731
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from lines of credit	0
Deferred issuance cost, gross	0
Line of Credit Facility, Increase, Borrowings Net Of Financing Costs	0
Repayment of debt and revolving credit facility	(40,000)		(74,500)
Amortization of deferred issuance cost	397
Debt Instrument, Decrease, Repayments Net of Amortization	(39,603)
Components of ending debt balance [Abstract]
Debt under credit facilities at end of period	220,500		220,500
Deferred issuance cost, net at end of period	(5,962)		(5,962)
Total Debt, net of deferred issuance cost at end of period	214,538		214,538
Long term debt, current portion, net of deferred issuance cost at end of period	8,410		8,410
Long term debt, net of deferred issuance cost at end of period	206,128		206,128
Wells Fargo Bank, National Association | Term Loan Facility
Components of beginning debt balance [Abstract]
Debt under credit facilities at beginning of period	192,500
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from lines of credit	0
Repayment of debt and revolving credit facility	(2,500)
Components of ending debt balance [Abstract]
Debt under credit facilities at end of period	190,000		190,000
Wells Fargo Bank, National Association | Revolving Credit Facility
Components of beginning debt balance [Abstract]
Debt under credit facilities at beginning of period	68,000
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from lines of credit	0
Repayment of debt and revolving credit facility	(37,500)
Components of ending debt balance [Abstract]
Debt under credit facilities at end of period	$ 30,500		$ 30,500