Accrued Expenses (Schedule Of Accrued Expenses) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Compensation related	$ 27,068	$ 20,936
Authority for expenditure accrual	379	141
Ad valorem taxes	5	171
Sales tax	2,590	1,343
Insurance obligations	6,174	3,576
Purchase order accrual		39
Professional fee accrual	497	564
Contingent earnout obligation	345	346
Fuel accrual	1,432	1,415
Accrued interest	17,711	14,364
Accrued expenses	65,096	51,237
Workers' Compensation [Member]
Self-insured risk reserve	4,967	3,968
Health Expense [Member]
Self-insured risk reserve	$ 3,928	$ 4,374