GOODWILL AND INTANGIBLE ASSETS (Intangible Assets) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite Lived And Indefinite Intangible Assets [Line Items]
Gross carrying value	$ 183,128,000	$ 150,382,000
Accumulated amortization	(80,778,000)	(71,745,000)
Net carrying value	102,350,000	78,637,000
Prepaid patent and trademark fees	1,000,000	900,000
Other intangible assets, net	100,900,000
Amortization expense	11,235,000	3,496,000	3,981,000
Domain Names
Finite Lived And Indefinite Intangible Assets [Line Items]
Other intangible assets	400,000
Trademarks
Finite Lived And Indefinite Intangible Assets [Line Items]
Other intangible assets	1,000,000
Minimum
Finite Lived And Indefinite Intangible Assets [Line Items]
Other intangible assets useful life (in years)	1 year
Maximum
Finite Lived And Indefinite Intangible Assets [Line Items]
Other intangible assets useful life (in years)	20 years
Customer lists
Finite Lived And Indefinite Intangible Assets [Line Items]
Gross carrying value	138,149,000	131,943,000
Accumulated amortization	(69,904,000)	(63,564,000)
Net carrying value	68,245,000	68,379,000
Non-compete agreements
Finite Lived And Indefinite Intangible Assets [Line Items]
Gross carrying value	13,170,000	9,436,000
Accumulated amortization	(6,891,000)	(5,851,000)
Net carrying value	6,279,000	3,585,000
Developed technology
Finite Lived And Indefinite Intangible Assets [Line Items]
Gross carrying value	23,000,000	1,000,000
Accumulated amortization	(1,843,000)	(1,000,000)
Net carrying value	21,157,000	0
Other
Finite Lived And Indefinite Intangible Assets [Line Items]
Gross carrying value	8,809,000	8,003,000
Accumulated amortization	(2,140,000)	(1,330,000)
Net carrying value	$ 6,669,000	$ 6,673,000