Long-term Debt and Line of Credit - Obligations under Debt Arrangements (Details) - USD ($) $ in Thousands	1 Months Ended
	Jun. 30, 2020	May 31, 2019	Mar. 31, 2019	Jul. 31, 2018	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Net Value, current					$ 4,348	$ 4,344
Net Value, long-term					$ 23,603	29,523
Line of Credit
Debt Instrument [Line Items]
Weighted average interest rate					2.48%
Principal current					$ 4,500	4,500
Principal, long-term					24,431	30,586
Principal					28,931	35,086
Deferred Issuance Costs, current					(152)	(156)
Deferred Issuance Costs, long-term					(828)	(1,063)
Debt Issuance Costs, Net, Total					(980)	(1,219)
Net Value, current					4,348	4,344
Net Value, long-term					23,603	29,523
Total debt					27,951	33,867
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					50,000
Debt issuance expense		$ 400
Principal, long-term						5,000
Deferred Issuance Costs, long-term						(174)
Net Value, long-term						4,826
Term Loan | Line of Credit
Debt Instrument [Line Items]
Principal current					4,500	4,500
Principal, long-term					24,431	25,586
Principal					28,931
Deferred Issuance Costs, current					(152)	(156)
Deferred Issuance Costs, long-term					(828)	(889)
Net Value, current					4,348	4,344
Net Value, long-term					23,603	$ 24,697
364-Day Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					20,000
Debt issuance expense	$ 400
Borrowings					0
Fourth, Fifth And Sixth Amendments To Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Debt Issuance Costs, Net, Total					$ (900)
Fourth Amendment to Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Debt issuance cost				$ 900
Fifth Amendment To Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Debt issuance cost			$ 600
Sixth Amendment To Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Debt issuance cost		$ 900