Goodwill and Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	$ 42,215	$ 35,682
Definite-lived, Accumulated Amortization	(28,380)	(24,321)
Definite-lived, Net Carrying Amount	13,835	11,361
Total other intangible assets, Gross Carrying Amount	51,285	44,752
Total other intangible assets, Accumulated Impairment	(4,953)	(4,953)
Total other intangible assets, Net Carrying Amount	17,952	15,478
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0
Amortization expense	$ 5,000	6,700	$ 9,500
Minimum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	2 years
Maximum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	5 years
Trade name
GOODWILL AND OTHER INTANGIBLE ASSETS
Indefinite lived, Gross Carrying Amount	$ 9,070	9,070
Indefinite lived, Accumulated Impairment	(4,953)	(4,953)
Indefinite lived, Net Carrying Amount	4,117	4,117
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0	200	$ 1,400
Customer lists
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	32,772	26,036
Definite-lived, Accumulated Amortization	(22,726)	(19,051)
Definite-lived, Net Carrying Amount	$ 10,046	6,985
Customer lists | Minimum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	4 years
Customer lists | Maximum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	10 years
Trade name
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	$ 255	255
Definite-lived, Accumulated Amortization	(151)	(125)
Definite-lived, Net Carrying Amount	$ 104	130
Trade name | Minimum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	1 year
Trade name | Trade name | Maximum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	10 years
Other intangible assets | Maximum
GOODWILL AND OTHER INTANGIBLE ASSETS
Amortized period of intangible assets	17 years
Patents and other intangibles
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	$ 9,188	9,391
Definite-lived, Accumulated Amortization	(5,503)	(5,145)
Definite-lived, Net Carrying Amount	$ 3,685	$ 4,246