Financial Statements Schedules Schedule I. Invesments Other Than Related Parties (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Open Option Contracts Written [Line Items]
Alternative Investment	$ 26,015		$ 32,211
Investments in private companies, at adjusted cost	3,090		4,870
Real Estate Investment Property, at Cost	10,225		10,225
Real estate investments, at fair value (cost of $10,225 and 10,225, respectively)	10,662		10,662	$ 10,662
Available-for-sale Securities			19,130
Debt Securities, Available-for-sale	12,260		14,541
Fixed maturities, cost	12,432		14,707
Available-for-sale Equity Securities, Amortized Cost Basis	2,274		4,868
Equity investments, at fair value (cost of $2,274 and $4,868, respectively)	856		4,589
Common Stock, Value, Outstanding	801		3,570
Available-for-sale Securities, Equity Securities	856		4,589
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	4,790		9,094
Other Investments	2,079		3,721
Short-term investments, at cost which approximates fair value	152		151
Investments, Cost Basis	60,432
Investment Owned, at Cost			3,633
Investments, Fair Value Disclosure	52,883
Investments	59,904		79,839
US States and Political Subdivisions Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	607		626
Fixed maturities, cost	621		639
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	3,186		2,876
Fixed maturities, cost	3,256		2,933
Corporate Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	2,920		5,427
Fixed maturities, cost	2,961		5,464
Equity Securities [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	2,274		4,868
Available-for-sale Securities, Equity Securities			4,589
Warrant [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	988
Available-for-sale Securities, Equity Securities	55
Common Stock [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	1,286		3,883
Available-for-sale Securities, Equity Securities			3,570
US Government Agencies Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	5,547		5,612
Fixed maturities, cost	5,594		5,671
Fair Value, Inputs, Level 2 [Member]
Open Option Contracts Written [Line Items]
Alternative Investment			10,314
Debt Securities, Available-for-sale	12,260
Available-for-sale Securities, Equity Securities	36		848
Investments	14,733		29,575
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	607		626
Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	3,186		2,876
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	2,920		5,427
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis			960
Available-for-sale Securities, Equity Securities			848
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	5,547		5,612
Fair Value, Inputs, Level 1 [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Securities, Equity Securities	820		3,741
Other Investments	0		0
Short-term investments, at cost which approximates fair value			0
Investments	820		3,741
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Open Option Contracts Written [Line Items]
Equity investments, at fair value (cost of $2,274 and $4,868, respectively)	801		3,570
Fair Value, Inputs, Level 1 [Member] | Warrant [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis			25
Available-for-sale Securities, Equity Securities			171
Fair Value, Inputs, Level 3 [Member]
Open Option Contracts Written [Line Items]
Alternative Investment	4,124		1,397	$ 939
Real estate investments, at fair value (cost of $10,225 and 10,225, respectively)	10,662	$ 10,662
Other Investments			0
Short-term investments, at cost which approximates fair value			0
Investments	14,786		12,059
Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale	0		0
Fair Value, Inputs, Level 3 [Member] | Common Stock [Member]
Open Option Contracts Written [Line Items]
Investments in private companies, at adjusted cost			1,397
Fair Value Measured at Net Asset Value Per Share [Member]
Open Option Contracts Written [Line Items]
Alternative Investment	21,685		20,500
Investment Owned, at Cost	2,465
Investments	21,685		20,500
US Government Agencies Debt Securities [Member]
Open Option Contracts Written [Line Items]
Available-for-sale Securities	$ 5,547		$ 5,612