Investments - Table of Investments by Segment (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Available for sale securities, at fair value		$ 255,784	$ 182,448
Loans, at fair value		229,033	258,173
Equity securities, at fair value		135,223	25,536
Other Investments		71,909	59,142
Total investments		691,949	525,299
Specialty Insurance
Segment Reporting Information [Line Items]
Available for sale securities, at fair value		255,784	182,448
Loans, at fair value		178,285	195,327
Equity securities, at fair value		32,812	25,536
Other Investments		28,834	50,720
Total investments		495,715	454,031
Asset Management
Segment Reporting Information [Line Items]
Available for sale securities, at fair value		0	0
Loans, at fair value		0	0
Equity securities, at fair value		0	0
Other Investments		1,460	2,846
Total investments		1,460	2,846
Mortgage
Segment Reporting Information [Line Items]
Available for sale securities, at fair value	[1]	0	0
Loans, at fair value	[1]	50,748	62,846
Equity securities, at fair value	[1]	0	0
Other Investments	[1]	4,986	5,013
Total investments	[1]	55,734	67,859
Corporate and Other
Segment Reporting Information [Line Items]
Available for sale securities, at fair value	[1],[2]	0	0
Loans, at fair value	[1],[2]	0	0
Equity securities, at fair value	[1],[2]	102,411	0
Other Investments	[1],[2]	36,629	563
Total investments	[1],[2]	$ 139,040	$ 563

[1] Investment income sourced from these investments is presented in Note (15) Other Revenue, Other Expenses and Other Income

[2] Does not include items related to assets held for sale. See Note (3) Dispositions, Assets Held for Sale & Discontinued Operations.