Fair Value of Financial Instruments - Assets Measured at Fair Value on Recurring and Nonrecurring Basis (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	$ 78,363,000		$ 78,363,000		$ 129,991,000
Equities	1,000		1,000		5,929,000
Fair value, available-for-sale securities	78,364,000		78,364,000		135,920,000
Fair value, assets, Level 1 to Level 2 transfers, amount	0	$ 0	0	$ 0
Fair value, assets, Level 2 to Level 1 transfers, amount	0	0	0	0
Fair value, asset transfers into Level 3	0	0	0	0
Fair value, asset transfers out of Level 3	0	$ 0	0	$ 0
US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	22,600,000		22,600,000		20,196,000
US States and Political Subdivisions Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	3,999,000		3,999,000		8,843,000
Total corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	15,619,000		15,619,000		42,351,000
Corporate Debt Securities, Banking and Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	5,183,000		5,183,000		13,124,000
Corporate Debt Securities, Consumer Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	2,430,000		2,430,000		9,790,000
Corporate Debt Securities, Capital Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	1,209,000		1,209,000		3,547,000
Corporate Debt Securities, Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	2,063,000		2,063,000		6,812,000
Corporate Debt Securities, Telecommunications and Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	4,302,000		4,302,000		8,323,000
Corporate Debt Securities, Health Care
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	432,000		432,000		755,000
Total Mortgage Backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	24,082,000		24,082,000		44,750,000
Fixed Income, U.S., Mortgage Backed, Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	11,203,000		11,203,000		25,128,000
Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	12,879,000		12,879,000		19,622,000
Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	12,063,000		12,063,000		13,851,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	22,600,000		22,600,000		20,196,000
Equities	1,000		1,000		5,929,000
Fair value, available-for-sale securities	22,601,000		22,601,000		26,125,000
Level 1 | US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	22,600,000		22,600,000		20,196,000
Level 1 | US States and Political Subdivisions Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Total corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Banking and Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Consumer Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Capital Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Telecommunications and Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Corporate Debt Securities, Health Care
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Total Mortgage Backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Fixed Income, U.S., Mortgage Backed, Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 1 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	55,763,000		55,763,000		109,795,000
Equities	0		0		0
Fair value, available-for-sale securities	55,763,000		55,763,000		109,795,000
Level 2 | US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 2 | US States and Political Subdivisions Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	3,999,000		3,999,000		8,843,000
Level 2 | Total corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	15,619,000		15,619,000		42,351,000
Level 2 | Corporate Debt Securities, Banking and Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	5,183,000		5,183,000		13,124,000
Level 2 | Corporate Debt Securities, Consumer Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	2,430,000		2,430,000		9,790,000
Level 2 | Corporate Debt Securities, Capital Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	1,209,000		1,209,000		3,547,000
Level 2 | Corporate Debt Securities, Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	2,063,000		2,063,000		6,812,000
Level 2 | Corporate Debt Securities, Telecommunications and Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	4,302,000		4,302,000		8,323,000
Level 2 | Corporate Debt Securities, Health Care
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	432,000		432,000		755,000
Level 2 | Total Mortgage Backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	24,082,000		24,082,000		44,750,000
Level 2 | Fixed Income, U.S., Mortgage Backed, Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	11,203,000		11,203,000		25,128,000
Level 2 | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	12,879,000		12,879,000		19,622,000
Level 2 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	12,063,000		12,063,000		13,851,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Equities	0		0		0
Fair value, available-for-sale securities	0		0		0
Level 3 | US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | US States and Political Subdivisions Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Total corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Banking and Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Consumer Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Capital Goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Telecommunications and Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Corporate Debt Securities, Health Care
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Total Mortgage Backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Fixed Income, U.S., Mortgage Backed, Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	0		0		0
Level 3 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	$ 0		$ 0		$ 0