INCOME TAXES (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of Deferred Tax Assets [Abstract]
Loss reserve discounting	$ 17,689,763				$ 18,669,516				$ 17,689,763	$ 18,669,516
Unearned premium reserve limitation	14,764,266				13,372,124				14,764,266	13,372,124
Retirement benefits	0				9,388,387				0	9,388,387
Other policyholders' funds payable	2,971,863				2,119,289				2,971,863	2,119,289
Other, net	1,761,100				1,726,687				1,761,100	1,726,687
Total deferred income tax asset	37,186,992				45,276,003				37,186,992	45,276,003
Net unrealized holding gains on investment securities	(26,048,567)				(37,587,475)				(26,048,567)	(37,587,475)
Deferred policy acquisition costs	(13,227,355)				(12,048,958)				(13,227,355)	(12,048,958)
Retirement benefits	(8,234,255)				0				(8,234,255)	0
Other, net	(2,498,475)				(1,992,260)				(2,498,475)	(1,992,260)
Total deferred income tax liability	(50,008,652)				(51,628,693)				(50,008,652)	(51,628,693)
Net deferred income tax liability	(12,821,660)				(6,352,690)				(12,821,660)	(6,352,690)
Income tax expense (benefit) reconciliation [Abstract]
United States federal corporate tax rate (in hundredths)									35.00%	35.00%	35.00%
Computed expected income tax expense (benefit)									21,298,347	18,071,765	(3,847,032)
Increases (decreases) in tax resulting from:
Tax-exempt interest income									(3,828,441)	(4,432,861)	(4,636,716)
Dividends received deduction									(876,421)	(722,900)	(516,691)
Proration of tax-exempt interest and dividends received deduction									705,729	773,364	773,011
Other, net									34,533	(22,183)	(26,810)
Total income tax expense (benefit)	6,995,658	2,365,223	1,736,419	6,236,447	5,498,854	2,429,112	(2,935,333)	8,674,552	17,333,747	13,667,185	(8,254,238)
Comprehensive Income Loss Tax [Abstract]
Operations	6,995,658	2,365,223	1,736,419	6,236,447	5,498,854	2,429,112	(2,935,333)	8,674,552	17,333,747	13,667,185	(8,254,238)
Change in unrealized holding gains on investment securities									(11,538,908)	10,043,215	7,463,995
Change in funded status of retirement benefit plans:
Pension plans									5,497,946	597,802	(3,132,777)
Postretirement benefit plans									12,103,023	349,988	(2,799,278)
Comprehensive income tax expense (benefit)									23,395,808	24,658,190	(6,722,298)
Provision for uncertain tax positions	0				0				0	0	0
Interest income related to US federal income taxes									0	3,359	0
Income Tax Examination, Penalties and Interest Expense									$ 0	$ 0	$ 0