Schedule I - Financial Information of the Registrant (Parent Company) - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 150,079	$ 185,772	$ 179,067	$ 200,558
Receivables:
Notes - due from subsidiaries	3,203	3,402
Allowance for uncollectible amounts	(5,156)	(9,647)
Total receivables	78,516	71,776
Property and equipment, at cost:
Furniture and equipment	226,461	217,105
Accumulated depreciation	(186,279)	(173,119)
Total property and equipment, at cost	67,022	70,506
Title plant, at cost	74,237	75,313
Investments in subsidiaries, on an equity-method basis	9,202	9,796
Goodwill	231,428	217,094	217,722
Other assets	47,664	42,975
Total assets	1,405,886	1,341,724
Liabilities
Notes payable	109,312	106,808
Accounts payable and other liabilities	117,740	115,640
Total Liabilities	727,076	692,876
Contingent liabilities and commitments
Stockholders’ equity
Common Stock – $1 par, authorized 50,000,000; issued 24,071,683 and 23,783,440; outstanding 23,719,522 and 23,431,279, respectively	24,072	23,783
Additional paid-in capital	159,954	157,176
Retained earnings	491,698	471,788
Accumulated other comprehensive (loss) income:
Foreign currency translation adjustments	(8,373)	(16,727)
Treasury stock – 352,161 common shares, at cost	(2,666)	(2,666)
Total stockholders’ equity	678,810	648,848	637,128	700,453
Total liabilities and stockholders' equity	1,405,886	1,341,724
Parent Company
Assets
Cash and cash equivalents	11,622	2,890	832	15,210
Receivables:
Notes - due from subsidiaries	26,316	40,879
Receivables from affiliates	930	848
Allowance for uncollectible amounts	(1)	(4)
Total receivables	27,245	41,723
Property and equipment, at cost:
Furniture and equipment	2,733	2,733
Accumulated depreciation	(2,517)	(2,512)
Total property and equipment, at cost	216	221
Title plant, at cost	48	48
Investments in subsidiaries, on an equity-method basis	731,975	688,837
Goodwill	8,470	8,470
Other assets	18,274	16,698
Total assets	797,850	758,887
Liabilities
Notes payable	98,875	92,875
Accounts payable and other liabilities	26,764	24,812
Total Liabilities	125,639	117,687
Contingent liabilities and commitments	0	0
Stockholders’ equity
Common Stock – $1 par, authorized 50,000,000; issued 24,071,683 and 23,783,440; outstanding 23,719,522 and 23,431,279, respectively	24,072	23,783
Additional paid-in capital	159,954	157,176
Retained earnings	491,698	471,788	$ 455,519	$ 479,733
Accumulated other comprehensive (loss) income:
Foreign currency translation adjustments	(8,373)	(16,727)
Unrealized investment gains	7,526	7,846
Treasury stock – 352,161 common shares, at cost	(2,666)	(2,666)
Total stockholders’ equity	672,211	641,200
Total liabilities and stockholders' equity	$ 797,850	$ 758,887