Landfill Accounting (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of the Company's final capping, closure and post-closure liability
Final capping, closure and post-closure liability at December 31, 2010	$ 28,537		$ 28,537
Adjustments to final capping, closure and post-closure liabilities	(1,281)
Liabilities incurred	1,029
Accretion expense	967	880
Closure payments	(354)
Final capping, closure and post-closure liability at June 30, 2011	28,898			28,537
Landfill Accounting (Textuals) [Abstract]
Number of landfills owned and operated by company	35
Number of landfills operated under life of site operating agreements	4
Number of landfills operated under limited-term operating agreements	5
Net book value landfill site costs	743,189
Number of owned landfills that only accept construction and demolition and other non-putrescible waste	2
Responsible for all final capping closure and post closure liabilities of landfills	3
Average remaining landfill life based on permitted capacity and projected annual disposal volumes	40 years
Number of owned landfills the company is seeking to expand	7
Number of landfills operated under life-of-site operating agreements that the company is seeking to expand	1
Average remaining landfill life based on permitted capacity, projected annual disposal volumes and probable expansion capacity	50 years
Life of Company's owned landfills and landfills operated under life of site operating agreements min range	1 year
Life of Company's owned landfills and landfills operated under life of site operating agreements max range	189 years
Landfill depletion expense	19,552	18,590
Average rate per ton consumed related to landfill depletion at owned landfills and landfills operated under life of site agreements	2.94	3.04
Discount rate for purposes of computing layers for final capping, closure and post-closure obligations			5.75%	6.50%
Inflation rate for purposes of computing layers for final capping, closure and post-closure obligations			2.50%	2.50%
Accretion expense	967	880
Average rate per ton consumed related to final capping, closure and post-closure landfill accretion expense	0.15	0.14
Restricted asset balance for purposes of securing our performance of future final capping, closure and post-closure obligations	$ 25,839