CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Cash flow from operating activities:
Net income	$ 104,089,748	$ 100,694,443	$ 91,249,180
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	1,365,473	1,698,241	1,949,444
Amortization of loan costs and discounts	612,021	311,624	441,895
Provision for loan losses	114,322,525	105,705,536	95,908,363
Amortization of convertible note discount	0	1,819,600	3,688,359
Depreciation	6,442,292	6,493,817	6,172,747
Deferred income tax benefit	(10,941,998)	(3,993,974)	(2,837,480)
Compensation related to stock option and restricted stock plans	11,165,327	6,617,827	5,340,707
Unrealized gains on interest rate swap	0	(319,235)	(1,017,032)
Change in accounts:
Other assets, net	(811,921)	(490,705)	1,017,199
Income taxes payable	2,413,396	(1,575,266)	(947,074)
Accounts payable and accrued expenses	3,387,226	2,439,394	(1,130,438)
Net cash provided by operating activities	232,044,089	219,401,302	199,835,870
Cash flows from investing activities:
Increase in loans receivable, net	(171,985,755)	(167,224,562)	(161,275,485)
Net assets acquired from office acquisitions, primarily loans	(1,951,646)	(3,383,421)	(2,977,729)
Increase in intangible assets from acquisitions	(716,169)	(869,189)	(746,666)
Purchases of property and equipment, net	(6,884,296)	(6,855,688)	(6,394,287)
Net cash used in investing activities	(181,537,866)	(178,332,860)	(171,394,167)
Cash flow from financing activities:
Borrowings from lines of credit	443,515,466	405,020,000	293,895,000
Payments on lines of credit	(272,515,466)	(258,020,000)	(310,795,000)
Repayment of convertible senior subordinated notes	0	(77,000,000)	0
(Payments on)/proceeds from junior subordinated note payable	(50,000,000)	20,000,000	30,000,000
Proceeds from sale of the call option and warrants associated with the convertible notes	0	0	1,092,949
Proceeds from exercise of stock options	9,944,601	9,588,160	11,882,632
Repurchase of common stock	(183,045,655)	(139,799,981)	(53,342,516)
Excess tax benefits from exercise of stock options	3,049,108	2,072,030	1,923,628
Net cash used in financing activities	(50,036,946)	(38,139,791)	(25,972,355)
(Decrease) increase in cash and cash equivalents	469,277	2,928,651	2,469,348
Effects of foreign currency fluctuations on cash	387,912	(191,055)	116,064
Cash and cash equivalents at beginning of period	10,768,176	8,030,580	5,445,168
Cash and cash equivalents at end of period	11,625,365	10,768,176	8,030,580
Junior subordinated notes payable [Member]
Cash flow from financing activities:
Payments of loan cost	0	0	(629,048)
Line of Credit [Member]
Cash flow from financing activities:
Payments of loan cost	$ (985,000)	$ 0	$ 0