SUPPLEMENTAL CASH FLOW & OTHER DATA (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Supplemental Cash Flow Elements [Abstract]
Depreciation expense	$ 52,037	$ 51,686	$ 102,895	$ 103,629
Amortization expense	19,759	20,169	39,119	40,400
Interest paid	32,180	32,208	83,971	81,990
Income taxes paid	120,981	192,556	204,938	202,809
Assets acquired under capital leases	1,995	1,763	2,411	2,955
Fair value of assets acquired	89,473		241,016	50,800
Fair value of liabilities assumed	154	0	10,962	269
Fair value of net assets acquired	89,319		230,054	50,531
Merger consideration paid (payable), net	237	12	(50,105)	37
Cash paid for business acquisitions	89,556	12	179,949	50,568
Less: Cash acquired	0	0	0	0
Business acquisitions, net of cash acquired	$ 89,556	$ 12	$ 179,949	$ 50,568