Investments Amortized cost, gross unrealized gains and losses, and estimated fair value (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, cost	$ 11,316		$ 14,707
Gross Unrealized Gain, Fixed Maturities	0		0
Gross Unrealized Loss, Fixed Maturities	240		166
Total Fixed Maturities	11,076		14,541
Equity investments, cost		$ 2,052	4,868
Total Equity Investments	1,577		4,589
Amortized Cost			19,575
Gross Unrealized Gain			319
Gross Unrealized Loss			764
Estimated Fair Value, Fixed Maturities and Equity Investments			19,130
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, cost	5,504		5,671
Gross Unrealized Gain, Fixed Maturities	0		0
Gross Unrealized Loss, Fixed Maturities	75		59
Total Fixed Maturities	5,429		5,612
Gross Unrealized Loss	75		59
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, cost	622		639
Gross Unrealized Gain, Fixed Maturities	0		0
Gross Unrealized Loss, Fixed Maturities	21		13
Total Fixed Maturities	601		626
Gross Unrealized Loss	21		13
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, cost	2,618		2,933
Gross Unrealized Gain, Fixed Maturities	0		0
Gross Unrealized Loss, Fixed Maturities	92		57
Total Fixed Maturities	2,526		2,876
Gross Unrealized Loss	92		57
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, cost	2,572		5,464
Gross Unrealized Gain, Fixed Maturities	0		0
Gross Unrealized Loss, Fixed Maturities	52		37
Total Fixed Maturities	2,520		5,427
Gross Unrealized Loss	52		37
Common Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Equity investments, cost			3,883
Total Equity Investments			3,570
Unrealized Gain, Equity Investments			0
Gross Unrealized Loss, Equity Investments			313
Gross Unrealized Loss			313
Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Loss			285
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Equity investments, cost			4,868
Total Equity Investments			4,589
Unrealized Gain, Equity Investments			319
Gross Unrealized Loss, Equity Investments			598
Gross Unrealized Loss			598
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	0		0
Total Equity Investments	1,205		3,741
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	0		0
Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	0		0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	0		0
Fair Value, Inputs, Level 1 [Member] | Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Equity investments, cost			25
Total Equity Investments			171
Unrealized Gain, Equity Investments			146
Gross Unrealized Loss, Equity Investments			0
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	11,076		14,541
Total Equity Investments	372		848
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	5,429		5,612
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	601		626
Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	2,526		2,876
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Fixed Maturities	$ 2,520		5,427
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Equity investments, cost			960
Total Equity Investments			848
Unrealized Gain, Equity Investments			173
Gross Unrealized Loss, Equity Investments			$ 285