Note 2 - Investment Securities (Details) - Amortized Cost and Fair Value of Investment Securities (USD $)	Jun. 30, 2014	Dec. 31, 2013
Securities held to maturity:
Securities held to maturity, amortized cost	$ 166,787,372	$ 145,451,895
Securities held to maturity, gross unrealized gains	1,492,583	299,789
Securities held to maturity, gross unrealized losses	(2,609,628)	(7,111,579)
Securities held to maturity, fair value	165,670,327	138,640,105
Securities available for sale:
Available for Sale Securities, amortized cost	521,322,159	573,870,562
Available for Sale Securities, gross unrealized gains	4,026,041	2,643,218
Available for Sale Securities, gross unrealized losses	(10,013,103)	(24,755,322)
Available for Sale Securities, fair value	515,335,097	551,758,458
US States and Political Subdivisions Debt Securities [Member]
Securities held to maturity:
Securities held to maturity, amortized cost	165,737,372	144,401,895
Securities held to maturity, gross unrealized gains	1,492,583	299,789
Securities held to maturity, gross unrealized losses	(2,609,628)	(7,111,579)
Securities held to maturity, fair value	164,620,327	137,590,105
Securities available for sale:
Available for Sale Securities, amortized cost	32,871,334	35,813,866
Available for Sale Securities, gross unrealized gains	1,156,141	923,315
Available for Sale Securities, gross unrealized losses	(170,004)	(778,324)
Available for Sale Securities, fair value	33,857,471	35,958,857
Other Securities [Member]
Securities held to maturity:
Securities held to maturity, amortized cost	1,050,000	1,050,000
Securities held to maturity, gross unrealized gains	0	0
Securities held to maturity, gross unrealized losses	0	0
Securities held to maturity, fair value	1,050,000	1,050,000
Securities available for sale:
Available for Sale Securities, amortized cost	1,401,827	1,372,365
Available for Sale Securities, gross unrealized gains	560,129	524,798
Available for Sale Securities, gross unrealized losses	0	0
Available for Sale Securities, fair value	1,961,956	1,897,163
US Government Agencies Debt Securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	334,083,927	376,574,132
Available for Sale Securities, gross unrealized gains	109,470	41,696
Available for Sale Securities, gross unrealized losses	(8,572,941)	(20,142,841)
Available for Sale Securities, fair value	325,620,456	356,472,987
Residential Mortgage Backed Securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	152,965,071	160,110,199
Available for Sale Securities, gross unrealized gains	2,200,301	1,153,409
Available for Sale Securities, gross unrealized losses	(1,270,158)	(3,834,157)
Available for Sale Securities, fair value	$ 153,895,214	$ 157,429,451