Business Segment Data - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 a Segment Commercial_Loan	Dec. 31, 2014 MortgageLoan	Dec. 31, 2013
Segment Reporting Information [Line Items]
Number of operating segment | Segment	4
Income property operation percent of identifiable asset	68.60%	68.70%
Income property operation percent of consolidated revenue	44.30%	41.50%	49.20%
Number of commercial loan investments | Commercial_Loan	4
Golf operation description	Our golf operations consist of a single property located in the City of Daytona Beach, with two 18-hole championship golf courses
Land portfolio | a	10,500
Commercial Mortgage Loan [Member]
Segment Reporting Information [Line Items]
Number of fixed-rate commercial mortgage loan investment		1
Mezzanine Loan [Member]
Segment Reporting Information [Line Items]
Number of fixed-rate commercial mortgage loan investment		1