Segment Reporting - Reconciliation of Operating Profit (Loss) from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of income from continuing operations from segments to consolidated [Abstract]
Total consolidated operating loss	$ 1,614	$ 470	$ (1,867)	$ (1,364)	$ (550)	$ 681	$ 915	$ (1,765)	$ (1,147)	$ (719)	$ (2,969)
Other income, net									3,187	3,280	3,703
Income from continuing operations before income taxes									$ 2,040	$ 2,561	$ 734