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Real Estate and Other Activities - Alecto Facilities - Additional Information (Detail) - Alecto Healthcare Services [Member]
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2020
USD ($)
Dec. 31, 2021
USD ($)
Property
Dec. 31, 2020
Property
Dec. 31, 2019
USD ($)
Business Acquisition [Line Items]        
Number of leased properties   4    
Real estate impairment charge | $ $ 9.1     $ 20.0
Number of re-leased properties     1  
Number of additional leased properties   1    
Proceeds from sale of mortgage loans | $   $ 51.0    
Total Gross Assets [Member] | Customer Concentration Risk [Member] | Maximum [Member]        
Business Acquisition [Line Items]        
Percentage of total assets   0.10%