Property, Plant And Equipment (Narrative) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property, Plant and Equipment [Line Items]
Interest capitalized on significant capital projects		$ 2,400,000	$ 1,100,000	$ 1,200,000
Amortization of capitalized interest included in depreciation		1,200,000	1,200,000	1,300,000
Accumulated amortization for assets under capital lease		1,489,948,000	1,433,865,000
Cash payments related to acquisitions		6,500,000	8,000,000
Net proceeds from sale of business	8,600,000
Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Depreciation		83,600,000	82,500,000	87,300,000
Accumulated amortization for assets under capital lease		$ 8,600,000	$ 7,600,000