Debt and Credit Agreements - Schedule of Long-term Debt Insturments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of debt balance [Abstract]
Long term debt, current portion, net of deferred issuance cost at beginning of period	$ 15,208
Debt Borrowing, Repayment, Amortization during period [Abstract]
Amortization of debt financing fees	2,292	$ 1,590	$ 1,590
Long term debt, current portion, net of deferred issuance cost at end of period	0	15,208
Long-term debt, net	135,417	194,917
Wells Fargo Bank, National Association
Components of debt balance [Abstract]
Debt under credit facilities at beginning of period	217,000
Deferred issuance cost, net at beginning of period	(6,875)
Total debt, net of deferred issuance cost	135,417	210,125
Long term debt, current portion, net of deferred issuance cost at beginning of period	15,208
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from debt	0
Debt issuance cost	0	(2,106)
Increase in borrowings net of deferred issuance cost	0
Repayment of debt and revolving credit facility	(77,000)
Amortization of debt financing fees	2,292	1,600	$ 1,600
Decrease in repayment/amortization net of deferred issuance cost	(74,708)
Debt under credit facilities at end of period	140,000	217,000
Deferred issuance cost, net at end of period	(4,583)	(6,875)
Long term debt, current portion, net of deferred issuance cost at end of period	0	15,208
Long-term debt, net	135,417	194,917
Term Loan Facility \| Wells Fargo Bank, National Association
Components of debt balance [Abstract]
Debt under credit facilities at beginning of period	182,500
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from debt	0
Repayment of debt and revolving credit facility	(42,500)
Debt under credit facilities at end of period	140,000	182,500
Revolving Credit Facility \| Wells Fargo Bank, National Association
Components of debt balance [Abstract]
Debt under credit facilities at beginning of period	34,500
Debt Borrowing, Repayment, Amortization during period [Abstract]
Proceeds from debt	0
Repayment of debt and revolving credit facility	(34,500)
Debt under credit facilities at end of period	$ 0	$ 34,500

Components of beginning debt balance [Abstract]

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Debt Borrowing, Repayment, Amortization during period [Abstract]

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Long-term Line of Credit, Gross

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Proceeds from Long-term Lines of Credit, Finance Costs

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Proceeds from Long-term Lines of Credit, Net of Financing Costs

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Repayments of Lines of Credit, Net of Financing Costs

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Amount of amortization expense attributable to debt issuance costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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