Debt, Debt Facilities (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019		Dec. 31, 2018		Apr. 18, 2018
Debt [Abstract]
Current portion of long-term debt		$ 25,000		$ 69,455
Credit Agreement [Member]
Debt [Abstract]
Unamortized debt issuance costs		3,300		4,000
Credit Agreement Term Loan Facility [Member]
Debt [Abstract]
Original principal amount		400,000				$ 400,000
Balance	[2]	$ 370,000	[1]	385,000
Interest rate		Variable 30 day: 3.79%
Interest rate		3.79%
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		$ 25,000
Credit Agreement Revolving Credit Facility [Member]
Debt [Abstract]
Balance		$ 0		$ 49,500	[2]
Interest rate		Variable 30 day: -
Interest rate		0.00%
Term of variable rate		30 days
Repayment terms		Revolving line of credit expires April 18, 2023.
Term of loan		5 years

[1] As of September 30, 2019, the current portion of the Company’s debt (i.e. becoming due in the next 12 months) included $25.0 million of the balance of its term loan under the Credit Agreement.

[2] The carrying value of the debt reflects the amounts stated in the above table less debt issuance costs of $3.3 million and $4.0 million as of September 30, 2019 and December 31, 2018, respectively, related to the Credit Agreement, which are not reflected in this table.