Schedule of Total Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 3,292,777	$ 3,272,398
Safety
Segment Reporting Information [Line Items]
Total assets	2,567,021	2,643,609
Community
Segment Reporting Information [Line Items]
Total assets	261,665	253,978
Properties
Segment Reporting Information [Line Items]
Total assets	285,623	220,235
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 178,468	$ 154,576