CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts Receivable, Current	$ 13,575	$ 12,683
Finite-Lived Intangible Assets, Accumulated Amortization	76,989	72,544
Accrued Capping, Closure, Post-closure and Environmental Costs	5,538	3,885
Accrued Environmental Loss Contingencies, Current	$ 13,115	$ 11,174
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	80,000,000	80,000,000
Common Stock, Shares, Issued	53,256,146	53,182,859
Common Stock, Shares, Outstanding	53,256,146	53,182,859