CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Statement of Financial Position [Abstract]
Accounts receivable, allowances aggregating	$ 14,285	$ 23,704
Permits and other intangibles, accumulated amortization	68,531	60,633
Closure and post-closure liabilities, current portion	5,086	5,849
Remedial liabilities, current portion	$ 10,813	$ 8,669
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares (in shares)	80,000,000	80,000,000
Common stock, issued shares (in shares)	53,038,399	52,772,392
Common stock, outstanding shares (in shares)	53,038,399	52,772,392