Long-Term Investments (Equity-Method Investments) (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 14, 2020	Oct. 09, 2019	Mar. 31, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 11, 2019
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 15,942	$ 11,631
Proceeds from long-term equity method investment					17,875	7,007	$ 1,239
Equity in earnings (losses) from investments					17,000	3,158	$ (765)
Indian Creek Investors LP (“Indian Creek”)
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 735	$ 1,167
Equity method ownership percentage					12.44%
Percent of other investments redeemed that qualify for the NAV practical expedient						50.00%
Boyar Value Fund (“Boyar”)
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 9,989	$ 8,384
Equity method ownership percentage					35.62%
Quoted market value					$ 9,989
Optika Fund LLC (“Optika”)
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 4,785	0
Equity method ownership percentage					9.14%
Contributions to equity method investments				$ 5,000
Ladenburg Thalmann Financial Services Inc. (“LTS”)
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 433	2,080
Equity method ownership percentage					10.22%
Quoted market value					$ 52,865
Difference between carrying value and underlying equity					$ 24,992
Investment owned (in shares)					15,191,205
Castle Brands
Schedule of Equity Method Investments [Line Items]
Equity-method investments					$ 0	0
Cash tender offer (in dollars per share)		$ 1.27
Tendered common shares (in shares)		12,895,017
Gain on sale of investment		$ 16,377
Maximum
Schedule of Equity Method Investments [Line Items]
Proceeds from long-term equity method investment						5,535
Minimum
Schedule of Equity Method Investments [Line Items]
Proceeds from long-term equity method investment						$ 1,472
Equity Method Investee | LTS Common Stock | Common Stock | Ladenburg Thalmann Financial Services Inc. (“LTS”)
Schedule of Equity Method Investments [Line Items]
Cash tender offer (in dollars per share)								$ 3.50
Equity Method Investee | LTS Common Stock | Common Stock | Subsequent Event | Ladenburg Thalmann Financial Services Inc. (“LTS”)
Schedule of Equity Method Investments [Line Items]
Proceeds from common shares of LTS	$ 53,169
Equity Method Investee | LTS Preferred | Series A Cumulative Redeemable Preferred Stock | Ladenburg Thalmann Financial Services Inc. (“LTS”)
Schedule of Equity Method Investments [Line Items]
Investment owned (in shares)					240,000
Preferred stock dividend rate					8.00%
Liquidation preference (in dollars per share)					$ 25.00
Forecast | Equity Method Investee | LTS Preferred | Series A Cumulative Redeemable Preferred Stock | Ladenburg Thalmann Financial Services Inc. (“LTS”)
Schedule of Equity Method Investments [Line Items]
Proceeds from common shares of LTS			$ 6,009