CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Statement of Financial Position [Abstract]
Accounts receivable, allowances aggregating	$ 12,683,000	$ 23,704,000
Permits and other intangibles, accumulated amortization	72,544,000	60,633,000
Closure and post-closure liabilities, current portion	3,885,000	5,849,000
Remedial liabilities, current portion	$ 11,174,000	$ 8,669,000
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)	53,182,859	52,772,392
Common stock, outstanding shares (in shares)	53,182,859	52,772,392