Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Accumulated deficit [Member]	Accumulated other comprehensive income (loss) [Member]	Treasury Stock [Member]	Common Class A [Member] Common Stock [Member]	Common Class B [Member] Common Stock [Member]
Balance at Dec. 31, 2018	$ 187,733	$ (69,599)	$ 5,366	$ (11,011)	$ 259,793	$ 3,184
Net income (loss)	(1,370)	(1,370)	0	0	0	0
Unrealized investment gains (losses), net	71,751	0	71,751	0	0	0
Total comprehensive income (loss)	70,381	(1,370)	71,751	0	0	0
Payments for Repurchase of Equity	0
Stock Issued During Period, Value, Stock Options Exercised	1,722	0	0	0	1,722	0
Balance at Dec. 31, 2019	259,836	(70,969)	77,117	(11,011)	261,515	3,184
Net income (loss)	(10,988)	(10,988)	0	0	0	0
Unrealized investment gains (losses), net	51,138	0	51,138	0	0	0
Total comprehensive income (loss)	40,150	(10,988)	51,138	0	0	0
Payments for Repurchase of Equity	0
Stock Issued During Period, Value, Stock Options Exercised	1,354	0	0	0	1,354	0
Balance at Dec. 31, 2020	300,945	(82,352)	128,255	(11,011)	262,869	3,184
Net income (loss)	36,787	36,787	0	0	0	0
Unrealized investment gains (losses), net	(10,763)	0	(10,763)	0	0	0
Total comprehensive income (loss)	26,024	36,787	(10,763)	0	0	0
Payments for Repurchase of Equity	(9,090)	0	0	(9,090)	0	0
Stock Issued During Period, Value, Stock Options Exercised	2,692	0	0	0	2,692	0
Balance at Dec. 31, 2021	$ 320,571	$ (45,565)	$ 117,492	$ (20,101)	$ 265,561	$ 3,184