Schedule II [Disclosure] - Condensed Statement of Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Investment income – interest and dividends	$ 4,444,447	$ 4,684,489	$ 4,531,319
Net realized gain (loss) on investments	1,040,901	768,436	(116,163)
Other	17,575,071	12,470,338	10,875,443
Total Revenues	161,649,296	138,492,414	127,200,072
Salaries, employee benefits and payroll taxes	39,012,354	31,372,099	28,041,213
Office occupancy and operations	8,966,623	6,265,908	5,885,336
Business development	3,164,730	2,511,699	2,373,270
Professional and contract labor fees	1,825,598	2,115,754	2,691,411
Other expenses	2,585,074	1,099,408	884,438
Income before Income Taxes	30,270,570	28,131,452	17,777,053
Income Tax Benefit	4,570,000	8,616,000	5,228,000
Net Income	25,700,570	19,515,452	12,549,053
Net Loss (Income) Attributable to Noncontrolling Interests	(5,932)	(7,666)	15,148
Net Income Attributable to the Company	$ 25,706,502	$ 19,523,118	$ 12,533,905
Basic Earnings per Common Share	$ 13.63	$ 10.23	$ 6.32
Weighted Average Shares Outstanding – Basic	1,886,354	1,907,675	1,984,360
Diluted Earnings per Common Share	$ 13.56	$ 10.19	$ 6.30
Weighted Average Shares Outstanding – Diluted	1,895,871	1,915,057	1,989,799
Common Stock, Dividends, Per Share, Declared	$ 3.75	$ 0.72	$ 0.40
Parent Company
Condensed Financial Statements, Captions [Line Items]
Investment income – interest and dividends	$ 501,653	$ 525,453	$ 535,963
Net realized gain (loss) on investments	35,834	77,895	(152,026)
Rental income	812,951	772,123	765,134
Other	220,497	77,074	385,058
Total Revenues	1,570,935	1,452,545	1,534,129
Salaries, employee benefits and payroll taxes	1,004,177	664,436	651,957
Office occupancy and operations	213,547	236,954	239,176
Business development	98,562	99,229	76,684
Taxes – other than payroll and income	396,084	183,566	213,466
Professional and contract labor fees	134,659	377,738	378,265
Other expenses	269,300	246,375	198,788
Total operating expenses	2,116,329	1,808,298	1,758,336
Equity in Net Income of Affiliated Companies	25,633,964	19,665,205	12,640,260
Income before Income Taxes	25,088,570	19,309,452	12,416,053
Income Tax Benefit	(612,000)	(206,000)	(133,000)
Net Income	25,700,570	19,515,452	12,549,053
Net Loss (Income) Attributable to Noncontrolling Interests	(5,932)	(7,666)	15,148
Net Income Attributable to the Company	$ 25,706,502	$ 19,523,118	$ 12,533,905
Basic Earnings per Common Share	$ 13.63	$ 10.23	$ 6.32
Weighted Average Shares Outstanding – Basic	1,886,354	1,907,675	1,984,360
Diluted Earnings per Common Share	$ 13.56	$ 10.19	$ 6.30
Weighted Average Shares Outstanding – Diluted	1,895,871	1,915,057	1,989,799
Common Stock, Dividends, Per Share, Declared	$ 3.75	$ 0.72	$ 0.40