GOODWILL AND OTHER INTANGIBLE ASSETS - Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	$ 45,981		$ 45,981		$ 52,259
Definite-lived, Accumulated Amortization	(32,136)		(32,136)		(34,619)
Definite-lived, Net Carrying Amount	13,845		13,845		17,640
Total other intangible assets, Gross Carrying Amount	55,051		55,051		61,329
Total other intangible assets, Accumulated Impairment	(4,770)		(4,770)		(4,770)
Total other intangible assets, Net Carrying Amount	18,145		18,145		21,940
Amortization expense	1,800	$ 2,400	3,800	$ 4,900
Trade Name
GOODWILL AND OTHER INTANGIBLE ASSETS
Indefinite life, Gross Carrying Amount	9,070		9,070		9,070
Indefinite life, Accumulated Impairment	(4,770)		(4,770)		(4,770)
Indefinite life, Net Carrying Amount	4,300		4,300		4,300
Customer lists
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	30,976		30,976		36,439
Definite-lived, Accumulated Amortization	(21,914)		(21,914)		(24,267)
Definite-lived, Net Carrying Amount	9,062		9,062		12,172
Other intangible assets
GOODWILL AND OTHER INTANGIBLE ASSETS
Definite-lived, Gross Carrying Amount	15,005		15,005		15,820
Definite-lived, Accumulated Amortization	(10,222)		(10,222)		(10,352)
Definite-lived, Net Carrying Amount	$ 4,783		$ 4,783		$ 5,468