CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021		Jun. 30, 2021		Mar. 31, 2021		Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020
Change in unrealized investment gains/losses, tax expense (benefit)	$ (2,166)		$ 4,992		$ (11,997)		$ 2,494		$ 8,829		$ (3,409)
Common stock: class A shares issued related to warrant exercises (in shares)	28,000
Common stock, par value (in dollars per share)	$ 0.01
Common stock
Common stock: class A shares issued related to warrant exercises (in shares)	27,715	[1]	8,096	[1]	23,750	[1]					6,474	[2]
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01		$ 0.01		$ 0.01				$ 0.01
Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes (in shares)	12,000	[1]	95,000		413,000		3,750	[2]	61,226	[2]	510,000

[1] During the three months ended March 31, 2021 and June 30, 2021, we issued 23,750 and 8,096 common shares, respectively, with a par value of $0.01 in connection with the exercise of warrants, which are not identifiable in this schedule due to rounding. During the three months ended September 30, 2021, we issued 27,715 common shares with a par value of $0.01 in connection with the exercise of warrants, and 12,436 common shares with a par value of $0.01 in connection with the exercise of options and vesting of restricted stock units granted under our stock plans, which are not identifiable in this schedule due to rounding.

[2] During the three months ended March 31, 2020, we issued 6,474 common shares with a par value of $0.01 in connection with the exercise of warrants, which is not identifiable in this schedule due to rounding. During the three months ended June 30, 2020 and September 30, 2020, we issued 61,226 and 3,750 common shares, respectively, with a par value of $0.01 in connection with the exercise of options and vesting of restricted stock units granted under our stock plans, which are not identifiable in this schedule due to rounding.