GOODWILL AND OTHER INTANGIBLE ASSETS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Total Goodwill and Intangible Assets [Roll Forward]
Balance at beginning of period			$ 144,958
Acquired during the year			81,417
Adjustment to prior year estimates			0
Amortization	(3,474)	(1,595)	(8,264)	(4,805)
Balance as of end of period	218,111		218,111
Goodwill [Roll Forward]
Balance at beginning of period			101,764
Acquired during the year			40,213
Adjustments to prior year estimates			(50)
Balance at end of period	141,927		141,927
Other Intangibles Assets [Roll Forward]
Balance at beginning of period			43,194
Acquired during the year			41,204
Adjustments to prior year estimates			50
Amortization	(3,474)	(1,595)	(8,264)	(4,805)
Balance at end of period	76,184		76,184
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	110,622		110,622		69,369
Accumulated amortization	(34,439)		(34,439)		(26,175)
Carrying amount, net	76,184		76,184		43,194
Vendor Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,496		2,496		2,496
Accumulated amortization	(1,050)		(1,050)		(956)
Carrying amount, net	1,446		1,446		1,540
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	104,076		104,076		64,262
Accumulated amortization	(31,382)		(31,382)		(23,508)
Carrying amount, net	72,694		72,694		40,754
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,050		4,050		2,611
Accumulated amortization	(2,007)		(2,007)		(1,711)
Carrying amount, net	$ 2,043		$ 2,043		$ 900