Reserves for Losses and Loss Settlement Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross liability for losses and loss settlement expenses at beginning of year	$ 1,578,131	$ 1,421,754	$ 1,312,483
Ceded losses and loss settlement expenses	(131,843)	(68,536)	(57,094)
Net liability for losses and loss settlement expenses at beginning of year	1,446,288	1,353,218	1,255,389
Losses and loss settlement expenses incurred for claims occurring during
Current year	701,064	887,119	835,507
Prior years	(48,909)	(17,652)	(5,335)
Total incurred	652,155	869,467	830,172
Losses and loss settlement expense payments for claims occurring during
Current year	277,115	354,635	333,975
Prior years	419,963	421,762	398,368
Total paid	697,078	776,397	732,343
Net liability for losses and loss settlement expenses at end of year	1,401,365	1,446,288	1,353,218
Ceded loss and loss settlement expenses	112,900	131,843	68,536
Gross liability for losses and loss settlement expenses at end of year	$ 1,514,265	$ 1,578,131	$ 1,421,754