Investment Funds (Schedule of Investment Funds) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure	$ 124,000
Investment funds	1,309,430	$ 1,213,535
Income (Losses)	54,253	69,194	$ 109,349
Financial services
Schedule of Equity Method Investments [Line Items]
Investment funds	434,437	280,705
Income (Losses)	34,763	29,005	11,044
Real estate
Schedule of Equity Method Investments [Line Items]
Investment funds	310,783	412,275
Income (Losses)	7,543	19,154	61,453
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds	140,935	156,869
Income (Losses)	(11,039)	(18,136)	7,084
Transportation
Schedule of Equity Method Investments [Line Items]
Investment funds	190,125	147,034
Income (Losses)	(616)	14,193	15,390
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds	233,150	216,652
Income (Losses)	$ 23,602	$ 24,978	$ 14,378

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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