Investments Amortized cost, gross unrealized gains and losses, and estimated fair value (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value [Abstract]
Alternative Investment	$ 26,015	$ 32,211
Debt Securities, Available-for-sale [Line Items]
Gain on change in fair value of equity investments	381	0
Total fixed maturities	12,432	14,707
Total equity investments	856	4,589
Total fixed maturities and equity investments		19,575
Gross Unrealized Gains, Fixed Maturities	1	0
Gross Unrealized Losses, Fixed Maturities	173	166
Estimated Fair Value, Fixed Maturities	12,260	14,541
Equity investments, cost	2,274	4,868
Gross Unrealized Gains		319
Gross Unrealized Losses		764
Estimated Fair Value, Fixed Maturities and Equity Investments		19,130
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities	5,594	5,671
Gross Unrealized Gains, Fixed Maturities	1	0
Gross Unrealized Losses, Fixed Maturities	48	59
Estimated Fair Value, Fixed Maturities	5,547	5,612
Gross Unrealized Losses	48	59
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities	621	639
Gross Unrealized Gains, Fixed Maturities	0	0
Gross Unrealized Losses, Fixed Maturities	14	13
Estimated Fair Value, Fixed Maturities	607	626
Gross Unrealized Losses	14	13
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities	3,256	2,933
Gross Unrealized Gains, Fixed Maturities	0	0
Gross Unrealized Losses, Fixed Maturities	70	57
Estimated Fair Value, Fixed Maturities	3,186	2,876
Gross Unrealized Losses	70	57
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities	2,961	5,464
Gross Unrealized Gains, Fixed Maturities	0	0
Gross Unrealized Losses, Fixed Maturities	41	37
Estimated Fair Value, Fixed Maturities	2,920	5,427
Gross Unrealized Losses	41	37
Common Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Total equity investments		3,570
Equity investments, cost	1,286	3,883
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax		0
Gross Unrealized Losses, Equity Investments		313
Gross Unrealized Losses		313
Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Total equity investments	55
Equity investments, cost	988
Gross Unrealized Losses		285
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total equity investments		4,589
Equity investments, cost	2,274	4,868
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax		319
Gross Unrealized Losses, Equity Investments		598
Gross Unrealized Losses		598
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities and Equity Investments	5,547	5,612
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-sale [Line Items]
Total equity investments	820	3,741
Fair Value, Inputs, Level 1 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, 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]
Estimated Fair Value, Fixed Maturities	0	0
Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities	0	0
Fair Value, Inputs, Level 1 [Member] \| Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Gain on change in fair value of equity investments		(112)
Total equity investments		171
Equity investments, cost		25
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax		146
Gross Unrealized Losses, Equity Investments		0
Fair Value, Inputs, Level 2 [Member]
Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value [Abstract]
Alternative Investment		10,314
Debt Securities, Available-for-sale [Line Items]
Total equity investments	36	848
Estimated Fair Value, Fixed Maturities	12,260
Fair Value, Inputs, Level 2 [Member] \| US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities	5,547	5,612
Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities	607	626
Fair Value, Inputs, Level 2 [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities	3,186	2,876
Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Fixed Maturities	$ 2,920	5,427
Fair Value, Inputs, Level 2 [Member] \| Warrant [Member]
Debt Securities, Available-for-sale [Line Items]
Total equity investments		848
Equity investments, cost		960
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax		173
Gross Unrealized Losses, Equity Investments		$ 285

Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value [Abstract]

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Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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