SUPPLEMENTAL BALANCE SHEET AND CASH FLOW INFORMATION (other) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in prepaid product discounts
Balance, beginning of year		$ 54,642	$ 63,895	$ 65,792
Additions	[1]	21,068	14,023	18,224
Amortization		(24,055)	(22,941)	(19,969)
Other		(510)	(335)	(152)
Balance, end of year		51,145	54,642	63,895
Prepaid product discount payments		25,637	23,814	27,079
Accrued liabilities
Deferred revenue	[2]	46,098	54,313
Employee cash bonuses		36,918	31,286
Prepaid product discounts due within one year		14,709	10,926
Operating lease liabilities		12,898	0
Customer rebates		8,944	9,555
Other		59,771	78,383
Accrued liabilities		179,338	184,463
Recognition of deferred revenue		51,386
Cash and cash equivalents		73,620	59,740	59,240
Cash, cash equivalents, restricted cash and restricted cash equivalents		174,811	145,259	128,819	$ 148,865
Income taxes paid		60,764	88,253	124,878
Interest paid		33,227	25,910	19,465
Non-cash investing activities [Line Items]
Proceeds from sales of businesses - notes receivable		1,685	35,616	24,497
Funds held for customers [Member]
Restricted cash and restricted cash equivalents included in funds held for customers		$ 101,191	$ 85,519	$ 69,579

[1] Prepaid product discounts are generally accrued upon contract execution. Cash payments made for prepaid product discounts were $25,637 for 2019, $23,814 for 2018 and $27,079 for 2017.

[2] $51,386 of the December 31, 2018 amount was recognized as revenue during 2019.