SUPPLEMENTAL CASH FLOW & OTHER DATA (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Supplemental Cash Flow & Other Data [Abstract]
Depreciation expense	$ 51,943	$ 53,516
Interest expense	(42,987)	(38,280)
Interest income	654	351
Interest expense, net	(42,333)	(37,929)
Interest paid	49,782	55,044
Income taxes paid	10,253	10,602
Assets acquired under capital lease obligations	1,192	821
Fair value of assets acquired	50,800
Fair value of liabilities assumed	269
Fair value of net assets acquired	50,531
Merger consideration paid	25
Cash paid for business acquisitions	50,556
Less: Cash acquired	0
Business acquisitions, net of cash acquired	$ 50,556