Schedule I - Financial Information of the Registrant (Parent Company) - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 248,367	$ 485,919
Property and equipment, at cost:
Accumulated depreciation	(153,474)	(165,653)
Total property and equipment, at cost	81,539	72,456
Investments in subsidiaries, on an equity-method basis	4,575	4,754
Operating lease assets	127,830	134,578
Goodwill	1,072,982	924,837	$ 431,477
Other assets	75,430	64,105
Total assets	2,737,879	2,813,362
Liabilities
Accounts payable and other liabilities	196,541	287,326
Operating lease liabilities	148,003	149,417
Notes payable	447,006	483,491
Total liabilities	1,367,614	1,518,627
Contingent liabilities and commitments
Stockholders’ equity
Common Stock – $1 par, authorized 51,500,000; issued 27,482,573 and 27,245,591; outstanding 27,130,412 and 26,893,430, respectively	27,483	27,246
Additional paid-in capital	296,861	282,376
Retained earnings	1,091,816	974,800
Accumulated other comprehensive income (loss) (AOCI):
Foreign currency translation adjustments	(23,856)	(8,917)
Net unrealized investment gains	(27,487)	9,170
Treasury stock – 352,161 common shares, at cost	(2,666)	(2,666)
Total stockholders’ equity	1,362,151	1,282,009
Total liabilities and stockholders' equity	2,737,879	2,813,362
Parent company
Assets
Cash and cash equivalents	31,912	15,527
Receivables from affiliates	49,055	21,519
Property and equipment, at cost:
Furniture and equipment	21	47
Accumulated depreciation	(21)	(46)
Total property and equipment, at cost	0	1
Investments in subsidiaries, on an equity-method basis	1,736,570	1,698,280
Operating lease assets	4,180	5,859
Goodwill	8,068	8,068
Other assets	16,730	19,659
Total assets	1,846,515	1,768,913
Liabilities
Accounts payable and other liabilities	24,036	24,829
Operating lease liabilities	5,720	7,961
Notes payable	454,608	454,106
Total liabilities	484,364	486,896
Contingent liabilities and commitments	0	0
Stockholders’ equity
Common Stock – $1 par, authorized 51,500,000; issued 27,482,573 and 27,245,591; outstanding 27,130,412 and 26,893,430, respectively	27,483	27,246
Additional paid-in capital	296,861	282,383
Retained earnings	1,091,816	974,800	$ 688,819	$ 564,392
Accumulated other comprehensive income (loss) (AOCI):
Foreign currency translation adjustments	(23,856)	(8,917)
Net unrealized investment gains	(27,487)	9,171
Treasury stock – 352,161 common shares, at cost	(2,666)	(2,666)
Total stockholders’ equity	1,362,151	1,282,017
Total liabilities and stockholders' equity	$ 1,846,515	$ 1,768,913