Consolidated Statements of Stockholder's Equity Statement - USD ($) $ in Thousands	Total	Accumulated deficit [Member]	Accumulated other comprehensive income [Member]	Treasury stock [Member]	Common Stock Class A [Member] Common stock [Member]	Common Stock Class B [Member] Common stock [Member]
Balance at Dec. 31, 2019	$ 259,836	$ (70,969)	$ 77,117	$ (11,011)	$ 261,515	$ 3,184
Net income (loss)	(3,584)	(3,584)	0	0	0	0
Unrealized investment gains (losses), net	(40,070)	0	(40,070)	0	0	0
Comprehensive income (loss)	(43,654)	(3,584)	(40,070)	0	0	0
Stock-based compensation	(53)	0	0	0	(53)	0
Balance at Mar. 31, 2020	215,734	(74,948)	37,047	(11,011)	261,462	3,184
Balance at Dec. 31, 2019	259,836	(70,969)	77,117	(11,011)	261,515	3,184
Net income (loss)	(4,611)	(4,611)
Unrealized investment gains (losses), net	34,577
Comprehensive income (loss)	29,966
Balance at Jun. 30, 2020	289,793	(75,975)	111,694	(11,011)	261,901	3,184
Balance at Mar. 31, 2020	215,734	(74,948)	37,047	(11,011)	261,462	3,184
Net income (loss)	(1,027)	(1,027)	0	0	0	0
Unrealized investment gains (losses), net	74,647	0	74,647	0	0	0
Comprehensive income (loss)	73,620	(1,027)	74,647	0	0	0
Stock-based compensation	439	0	0	0	439	0
Balance at Jun. 30, 2020	289,793	(75,975)	111,694	(11,011)	261,901	3,184
Balance at Dec. 31, 2020	300,945	(82,352)	128,255	(11,011)	262,869	3,184
Net income (loss)	(3,573)	(3,573)	0	0	0	0
Unrealized investment gains (losses), net	(56,518)	0	(56,518)	0	0	0
Comprehensive income (loss)	(60,091)	(3,573)	(56,518)	0	0	0
Stock-based compensation	(14)	0	0	0	(14)	0
Balance at Mar. 31, 2021	240,840	(85,925)	71,737	(11,011)	262,855	3,184
Balance at Dec. 31, 2020	300,945	(82,352)	128,255	(11,011)	262,869	3,184
Net income (loss)	1,449	1,449
Unrealized investment gains (losses), net	(24,370)
Comprehensive income (loss)	(22,921)
Balance at Jun. 30, 2021	269,125	(80,903)	103,885	(20,101)	263,060	3,184
Balance at Mar. 31, 2021	240,840	(85,925)	71,737	(11,011)	262,855	3,184
Net income (loss)	5,022	5,022	0	0	0	0
Unrealized investment gains (losses), net	32,148	0	32,148	0	0	0
Comprehensive income (loss)	37,170	5,022	32,148	0	0	0
Treasury Stock, Value, Acquired, Cost Method	(9,090)	0	0	(9,090)	0	0
Stock-based compensation	205	0	0	0	205	0
Balance at Jun. 30, 2021	$ 269,125	$ (80,903)	$ 103,885	$ (20,101)	$ 263,060	$ 3,184