Long-Term Investments (Combined Financial Statements for Unconsolidated Subsidiaries Accounted for on Equity Method) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Castle Brands
Schedule of Equity Method Investments [Line Items]
Current assets		$ 57,047		$ 49,328
Non-current assets		8,359		8,783
Total assets		65,406		58,111
Current liabilities		13,440		17,586
Non-current liabilities		42,892		35,296
Total liabilities		56,332		52,882
Non-controlling interest		4,167		2,843
Non-controlling interest		4,907		2,386
Partners’ capital		9,074		5,229
Total liabilities and partners’ capital		65,406		58,111
Revenues		94,567		82,636		$ 73,549
Expenses		57,083		48,257		44,236
Gross profit		37,484		34,379		29,313
Other expenses		32,769		31,404		28,338
Income from continuing operations		4,715		2,975		975
Net income (loss)		546		1,008		(1,263)
Ladenburg Thalmann Financial Services
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents		262,834		100,739
Receivables from clearing brokers, note receivable and other receivable, net		165,149		139,497
Goodwill and intangible assets, net		200,199		233,007
Other assets		172,409		79,372
Total assets		800,591		552,615
Other liabilities		37,658		31,718
Accrued compensation, commissions and fees payable		141,260		90,991
Accounts payable and accrued liabilities		50,122		42,895
Notes payable, net of $115 and $535 unamortized discount in 2018 and 2017, respectively		185,199		28,182
Unamortized discount		115		535
Total liabilities		414,239		193,786
Preferred stock		2		2
Common stock		20		20
Additional paid-in capital		487,752		515,208
Accumulated deficit		(101,467)		(156,423)
Non-controlling interest		386,307		358,807
Non-controlling interest		45		22
Partners’ capital		386,352		358,829
Total liabilities and partners’ capital		800,591		552,615
Revenues		1,380,031		1,221,195		1,104,227
Expenses		1,345,768		1,217,331		1,119,366
Gross profit		34,263		3,864		(15,139)
Change in fair value of contingent consideration		(232)		48		(154)
Income from continuing operations		34,031		3,912		(15,293)
Net income (loss)		$ 30,858		$ 1,669		$ (25,159)
Indian Creek and Boyar Value Fund
Schedule of Equity Method Investments [Line Items]
Investment securities	$ 33,830		$ 48,050
Cash and cash equivalents	521		1,719
Other assets	33		74
Total assets	34,384		49,843
Other liabilities	738		3,007
Total liabilities	738		3,007
Partners’ capital	33,646		46,836
Total liabilities and partners’ capital	34,384		49,843
Revenues	549		792		$ 438
Expenses	861		690		684
Gross profit	(312)		102		(246)
Total net realized (loss) gain and net change in unrealized depreciation from investments	(5,781)		100		3,341
Income from continuing operations	$ (6,093)		$ 202		$ 3,095