CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Revenues:
Interest and fee income	$ 505,495,331	$ 466,481,109	$ 424,594,245
Insurance commissions and other income	78,222,382	73,680,573	66,850,858
Total revenues	583,717,713	540,161,682	491,445,103
Expenses:
Provision for loan losses	114,322,525	105,705,536	95,908,363
General and administrative expenses:
Personnel	194,422,717	175,402,913	159,160,492
Occupancy and equipment	36,278,134	33,864,579	31,115,076
Advertising	14,849,980	14,228,002	13,056,444
Amortization of intangible assets	1,365,473	1,698,241	1,949,444
Other	38,794,090	35,490,422	32,233,478
Total general and administrative expenses	285,710,394	260,684,157	237,514,934
Interest expense	17,393,963	13,898,648	14,772,694
Total expenses	417,426,882	380,288,341	348,195,991
Income before income taxes	166,290,831	159,873,341	143,249,112
Income taxes	62,201,083	59,178,898	51,999,932
Net income	$ 104,089,748	$ 100,694,443	$ 91,249,180
Net income per common share:
Basic (in dollars per share)	$ 8.04	$ 6.75	$ 5.76
Diluted (in dollars per share)	$ 7.88	$ 6.59	$ 5.63
Weighted average common shares outstanding:
Basic (in shares)	12,940,007	14,906,662	15,833,983
Diluted (in shares)	13,214,271	15,289,111	16,210,233