Supplemental Disclosure of Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Acquisition of assets, net of related payables and cash received [Abstract]
Interest paid	$ 30,049	$ 31,606
Income taxes paid	207	192
Write-off of deferred costs	744	313
Series Of Individually Immaterial Business Acquisitions [Member]
Acquisition of assets, net of related payables and cash received [Abstract]
Property, plant and equipment and leasehold intangibles, net	121,250	50,366
Other intangible assets, net	3,672	982
Cash and escrow deposits - restricted	3,313	0
Prepaid expenses and other current assets, net	(2,817)	0
Other assets, net	(7,327)	0
Long-term debt, less current portion	(15,000)	0
Accrued expenses	(392)	(18)
Other liabilities	4,429	0
Accumulated earnings	(2,144)	0
Net	$ 104,984	$ 51,330