Landfill Accounting (Reconciliation of Final Capping, Closure and Post-Closure Liability Balance) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Landfill Accounting [Abstract]
Final capping, closure and post-closure liability at the beginning of the period	$ 50,128
Adjustments to final capping, closure and post-closure liabilities	2,113
Liabilities incurred	2,782
Accretion expense associated with landfill obligations	2,445	2,077
Closure payments	(48)
Assumption of closure liabilities from acquisitions	120
Final capping, closure and post-closure liability at the end of the period	$ 57,540