Supplemental Financial Information (Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Income Statement Elements [Abstract]
Interest on revolving credit facility	$ 101	$ 1,079
Interest rate swap settlements	0	86
Line of credit fees	273	166
Debt issuance amortization costs	179	138
Interest on finance leases	212	33
Interest income	(195)	(320)
Other	38	25
Total interest expense, net	$ 608	$ 1,207