INVESTMENTS (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	$ 1,034,733,515		$ 1,032,695,902
Gross unrealized gains	116,919,960		108,828,734
Gross unrealized losses	1,628,318		1,435,954
Estimated fair value	1,150,025,157		1,140,088,682
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	93,292,578		68,639,279
Twelve months or longer, Fair value	8,031,020		1,884,000
Total, Fair value	101,323,598		70,523,279
Less than twelve months, Unrealized losses	1,382,127		1,319,954
Twelve months or longer, Unrealized losses	246,191		116,000
Total, Unrealized losses	1,628,318		1,435,954
Securities available-for-sale, Amortized cost [Abstract]
Due in one year or less	18,153,853
Due after one year through five years	157,229,654
Due after five years through ten years	144,708,701
Due after ten years	478,155,543
Mortgage-backed securities	121,946,482
Totals	920,194,233
Securities available-for-sale, Estimated fair value [Abstract]
Due in one year or less	18,431,127
Due after one year through five years	169,194,856
Due after five years through ten years	159,959,589
Due after ten years	513,689,150
Mortgage-backed securities	132,839,637
Totals	994,114,359		999,794,857
Available-for-sale securities, gross realized gain (loss) [Abstract]
Available-for-sale, "Other-than-temporary" impairments	20,608	0
Net realized investment gains	2,667,873	8,918,329
Debt securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	920,194,233		920,843,939
Gross unrealized gains	75,225,347		79,822,707
Gross unrealized losses	1,305,221		871,789
Estimated fair value	994,114,359		999,794,857
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	86,684,747		63,828,814
Twelve months or longer, Fair value	6,079,020		0
Total, Fair value	92,763,767		63,828,814
Less than twelve months, Unrealized losses	1,107,030		871,789
Twelve months or longer, Unrealized losses	198,191		0
Total, Unrealized losses	1,305,221		871,789
Available-for-sale securities, gross realized gain (loss) [Abstract]
Available-for-sale, Gross realized investment gains	686,573	400,491
Debt securities [Member] | U.S. treasury [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	4,701,810		4,697,762
Gross unrealized gains	268,989		287,140
Gross unrealized losses	0		0
Estimated fair value	4,970,799		4,984,902
Debt securities [Member] | U.S. government-sponsored agencies [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	159,310,701		159,548,303
Gross unrealized gains	3,043,847		3,228,302
Gross unrealized losses	582,239		333,975
Estimated fair value	161,772,309		162,442,630
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	52,277,432		33,950,271
Twelve months or longer, Fair value	0		0
Total, Fair value	52,277,432		33,950,271
Less than twelve months, Unrealized losses	582,239		333,975
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	582,239		333,975
Debt securities [Member] | Obligations of states and political subdivisions [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	329,329,828		335,188,220
Gross unrealized gains	33,894,967		35,776,373
Gross unrealized losses	67,715		2,479
Estimated fair value	363,157,080		370,962,114
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	3,163,650		3,234,180
Twelve months or longer, Fair value	0		0
Total, Fair value	3,163,650		3,234,180
Less than twelve months, Unrealized losses	67,715		2,479
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	67,715		2,479
Debt securities [Member] | Commercial mortgage-backed [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	63,490,507		69,952,036
Gross unrealized gains	9,200,136		10,412,989
Gross unrealized losses	16,903		15,843
Estimated fair value	72,673,740		80,349,182
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	5,973,340		3,773,043
Twelve months or longer, Fair value	832,103		0
Total, Fair value	6,805,443		3,773,043
Less than twelve months, Unrealized losses	8,843		15,843
Twelve months or longer, Unrealized losses	8,060		0
Total, Unrealized losses	16,903		15,843
Debt securities [Member] | Residential mortgage-backed [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	58,455,975		46,286,598
Gross unrealized gains	1,927,975		1,777,113
Gross unrealized losses	218,053		274,107
Estimated fair value	60,165,897		47,789,604
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	6,709,177		5,303,741
Twelve months or longer, Fair value	0		0
Total, Fair value	6,709,177		5,303,741
Less than twelve months, Unrealized losses	218,053		274,107
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	218,053		274,107
Debt securities [Member] | Other asset-backed [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	9,139,115		9,720,662
Gross unrealized gains	1,471,606		1,566,186
Gross unrealized losses	0		0
Estimated fair value	10,610,721		11,286,848
Debt securities [Member] | Corporate [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	295,766,297		295,450,358
Gross unrealized gains	25,417,827		26,774,604
Gross unrealized losses	420,311		245,385
Estimated fair value	320,763,813		321,979,577
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	18,561,148		17,567,579
Twelve months or longer, Fair value	5,246,917		0
Total, Fair value	23,808,065		17,567,579
Less than twelve months, Unrealized losses	230,180		245,385
Twelve months or longer, Unrealized losses	190,131		0
Total, Unrealized losses	420,311		245,385
Equity securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	114,539,282		111,851,963
Gross unrealized gains	41,694,613		29,006,027
Gross unrealized losses	323,097		564,165
Estimated fair value	155,910,798		140,293,825
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	6,607,831		4,810,465
Twelve months or longer, Fair value	1,952,000		1,884,000
Total, Fair value	8,559,831		6,694,465
Less than twelve months, Unrealized losses	275,097		448,165
Twelve months or longer, Unrealized losses	48,000		116,000
Total, Unrealized losses	323,097		564,165
Available-for-sale securities, gross realized gain (loss) [Abstract]
Available-for-sale, Gross realized investment gains	2,090,607	8,605,675
Available-for-sale, Gross realized investment losses	(88,699)	(87,837)
Available-for-sale, "Other-than-temporary" impairments	(20,608)	0
Equity securities [Member] | Financial services [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	17,836,200		14,496,766
Gross unrealized gains	5,873,482		3,630,544
Gross unrealized losses	5,051		33,922
Estimated fair value	23,704,631		18,093,388
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	793,858		881,580
Twelve months or longer, Fair value	0		0
Total, Fair value	793,858		881,580
Less than twelve months, Unrealized losses	5,051		33,922
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	5,051		33,922
Equity securities [Member] | Common stocks Information technology [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	10,214,044		12,331,378
Gross unrealized gains	4,731,138		4,722,076
Gross unrealized losses	17,389		127,690
Estimated fair value	14,927,793		16,925,764
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	129,858		1,435,122
Twelve months or longer, Fair value	0		0
Total, Fair value	129,858		1,435,122
Less than twelve months, Unrealized losses	17,389		127,690
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	17,389		127,690
Equity securities [Member] | Common stocks Healthcare [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	14,348,658		14,823,967
Gross unrealized gains	6,842,978		4,199,882
Gross unrealized losses	0		0
Estimated fair value	21,191,636		19,023,849
Equity securities [Member] | Common stocks consumer staples [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	12,518,195		12,019,892
Gross unrealized gains	3,641,083		1,593,039
Gross unrealized losses	0		3,404
Estimated fair value	16,159,278		13,609,527
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value			90,080
Twelve months or longer, Fair value			0
Total, Fair value			90,080
Less than twelve months, Unrealized losses			3,404
Twelve months or longer, Unrealized losses			0
Total, Unrealized losses			3,404
Equity securities [Member] | Common stocks consumer discretionary [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	9,667,997		10,829,547
Gross unrealized gains	7,931,936		6,261,000
Gross unrealized losses	0		0
Estimated fair value	17,599,933		17,090,547
Equity securities [Member] | Common stocks energy [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	16,486,079		14,629,926
Gross unrealized gains	6,941,549		4,800,404
Gross unrealized losses	165,787		0
Estimated fair value	23,261,841		19,430,330
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	3,462,866
Twelve months or longer, Fair value	0
Total, Fair value	3,462,866
Less than twelve months, Unrealized losses	165,787
Twelve months or longer, Unrealized losses	0
Total, Unrealized losses	165,787
Equity securities [Member] | Common stocks industrials [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	7,993,453		7,638,633
Gross unrealized gains	1,932,862		936,183
Gross unrealized losses	0		0
Estimated fair value	9,926,315		8,574,816
Equity securities [Member] | Common stocks other [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	17,142,219		16,749,417
Gross unrealized gains	3,149,263		2,215,172
Gross unrealized losses	86,870		283,149
Estimated fair value	20,204,612		18,681,440
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	2,221,249		2,403,683
Twelve months or longer, Fair value	0		0
Total, Fair value	2,221,249		2,403,683
Less than twelve months, Unrealized losses	86,870		283,149
Twelve months or longer, Unrealized losses	0		0
Total, Unrealized losses	86,870		283,149
Equity securities [Member] | Non-redeemable preferred stocks [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	8,332,437		8,332,437
Gross unrealized gains	650,322		647,727
Gross unrealized losses	48,000		116,000
Estimated fair value	8,934,759		8,864,164
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	0		0
Twelve months or longer, Fair value	1,952,000		1,884,000
Total, Fair value	1,952,000		1,884,000
Less than twelve months, Unrealized losses	0		0
Twelve months or longer, Unrealized losses	48,000		116,000
Total, Unrealized losses	$ 48,000		$ 116,000