Debt, Debt Facilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019		Dec. 31, 2018	Apr. 18, 2018
Debt [Abstract]
Current portion of long-term debt	$ 59,500		$ 69,455
Credit Agreement [Member]
Debt [Abstract]
Unamortized debt issuance costs	3,500		4,000
Credit Agreement Term Loan Facility [Member]
Debt [Abstract]
Original principal amount	400,000			$ 400,000
Balance	$ 375,000	[1],[2]	385,000
Interest rate	Variable 30 day: 4.15%
Interest rate	4.15%
Term of variable rate	30 days
Repayment terms	35% of the principal amount is payable in increasing quarterly installments over a five-year period that began on June 30, 2018, with the remainder payable at the end of the five-year term.
Percentage of principal payable in installments	35.00%
Term of loan	5 years
Current portion of long-term debt	$ 22,500
Credit Agreement Revolving Credit Facility [Member]
Debt [Abstract]
Balance	$ 37,000	[1],[2]	$ 49,500
Interest rate	Variable 30 day: 4.15%
Interest rate	4.15%
Term of variable rate	30 days
Repayment terms	Revolving line of credit expires April 18, 2023.
Term of loan	5 years
Current portion of long-term debt	$ 37,000

[1] As of June 30, 2019, the current portion of the Company’s debt (i.e. becoming due in the next 12 months) included $22.5 million of the balance of its term loan under the Credit Agreement. The Company has classified the $37.0 million borrowed under the revolving line of credit as current debt because it is the Company’s intention to use the line of credit to borrow and pay back funds over short periods of time.

[2] The carrying value of the debt reflects the amounts stated in the above table less debt issuance costs of $3.5 million and $4.0 million as of June 30, 2019 and December 31, 2018, respectively, related to the Credit Agreement, which are not reflected in this table.