Schedule of Total Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 3,584,032	$ 3,272,398
Safety
Segment Reporting Information [Line Items]
Total assets	2,561,247	2,643,609
Community
Segment Reporting Information [Line Items]
Total assets	257,919	253,978
Properties
Segment Reporting Information [Line Items]
Total assets	576,491	220,235
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 188,375	$ 154,576