Other Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 77,204	$ 77,309
Less accumulated amortization and impairment:	(69,490)	(67,481)
Intangible assets, net	7,714	9,828
Customer lists
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	73,678	73,792
Less accumulated amortization and impairment:	$ (66,382)	(64,528)
Weighted Average Life in Years	13 years 7 months 6 days
Non-competition agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 959	950
Less accumulated amortization and impairment:	$ (959)	(950)
Weighted Average Life in Years	4 years 1 month 6 days
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 2,510	2,510
Less accumulated amortization and impairment:	$ (2,098)	(1,956)
Weighted Average Life in Years	13 years 3 months 18 days
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 57	57
Less accumulated amortization and impairment:	$ (51)	$ (47)
Weighted Average Life in Years	9 years