Supplemental Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Supplemental Income Statement Elements [Abstract]
Interest on revolving credit facility	$ 1,079	$ 2,251
Interest rate swap settlements	86	(122)
Line of credit fees	166	126
Debt issuance amortization costs	138	138
Interest on finance leases	33	32
Interest income	(320)	(489)
Depreciation on leased assets	0	1,185
Total interest expense, net	25	2
Total interest expense, net	$ 1,207	$ 1,938