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Investments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Sep. 08, 2017
Investment [Line Items]
Equity Income			$ 6,000	$ 5,000
Equity method investments	$ 99,966		99,966		$ 101,275
Other Assets [Member]
Investment [Line Items]
Equity method investments	100,000		100,000		101,300
Alternative investment	$ 102,400		$ 102,400		$ 53,500
CF Real Estate Finance Holdings, L.P. [Member]
Investment [Line Items]
Equity method investments						$ 100,000
Equity method investment ownership percentage	27.00%		27.00%
Other Income, Net [Member]
Investment [Line Items]
Equity Income	$ 1,300	$ 0	$ 6,000	$ 5,000
Distributions received	7,300		7,300
Realized and unrealized gains, net	$ 17,100		$ 21,000