Contract Receivable (Details) $ in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) bed	Dec. 31, 2019 AUD ($)	Dec. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract receivable	$ 360,647		$ 368,178
Ravenhall
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract receivable	$ 371,800
Loan issued, interest rate	8.97%
National Australia Bank Limited | Non Recourse Debt | Ravenhall
Accounts, Notes, Loans and Financing Receivable [Line Items]
Capital contribution	$ 80,700	$ 115
Lump sum due at completion	$ 217,400	$ 310
Department Of Justice, State Of Victoria | Facility Constructions and Design
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of beds in detention facility | bed	1,300
Facility operation contract term	25 years