Commitments And Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 1997
Loss Contingencies [Line Items]
Issuance of revenue bonds		$ 72.7
Outstanding principal balance of revenue bonds	33.4
Outstanding principal balance of the bonds exceeded the purchase price option	$ 11.1
Number of pending legal proceedings that would have an effect on consolidated financial position, results of operations, or cash flows	0
Hardeman County Correctional Facilities Corporation [Member]
Loss Contingencies [Line Items]
Number of beds at the facility		2,016