Business Combinations (Details)		3 Months Ended								9 Months Ended	12 Months Ended
	Feb. 17, 2015 USD ($) facility bed	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Sep. 30, 2015	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 615,438,000				$ 493,890,000					$ 615,438,000	$ 493,890,000	$ 490,196,000
Revenues		500,127,000	$ 469,866,000	$ 445,945,000	$ 427,369,000	427,740,000	$ 457,900,000	$ 412,843,000	$ 393,137,000		1,843,307,000	1,691,620,000	1,522,074,000
Income from Continuing Operations						$ 37,981,000	$ 38,965,000	$ 38,898,000	$ 27,996,000		139,315,000	$ 143,840,000	$ 117,462,000
LCS Facilities
Business Acquisition [Line Items]
Number of correctional and detention facilities acquired | facility	8
Number of beds In facilities acquired (more than 6,500) | bed	6,500
Total consideration paid	$ 307,403,000
Goodwill	107,398,000
Contingent consideration arrangements, performance period										18 months
Aggregate amount of purchase price, maximum		350,000,000									350,000,000
Contingent consideration value	0
Repayments of debt	$ 298,000,000
Revenues											55,500,000
Income from Continuing Operations											$ 8,500,000
LCS Facilities | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets, useful life										20 years
LCS Facilities | General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related costs		$ 2,500,000