CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comp. Income (Loss)
Balance at Mar. 31, 2010	$ 221,768	$ 6,008	$ 97,819	$ 117,908	$ 33
Balance (in shares) at Mar. 31, 2010		9,013,508
Increase (decrease) in stockholders' equity
Net income	42,817			42,817
Repurchase of common stock	(3,736)	(34)	(3,702)
Repurchase of common stock (in shares)		(51,269)
Exercise of stock options	6,943	132	6,811
Exercise of stock options (in shares)		197,669
Issuance of stock under employee compensation plans	220	2	218
Issuance of stock under employee compensation plans (in shares)		2,939
Issuances of restricted stock, net of forfeitures		5	(5)
Issuances of restricted stock, net of forfeitures (in shares)		7,118
Tax benefit accrued on stock option exercises / (reversal) associated with stock options	3,730		3,730
Compensation expense on stock options	1,703		1,703
Compensation expense on restricted stock and restricted stock units	3,513		3,513
Dividends declared	(10,866)			(10,866)
Net change in unrealized losses on investment securities, available-for-sale, net of tax	(12)				(12)
Balance at Mar. 31, 2011	266,080	6,113	110,087	149,859	21
Balance (in shares) at Mar. 31, 2011		9,169,965
Increase (decrease) in stockholders' equity
Net income	21,422			21,422
Repurchase of common stock	(20,051)	(213)	(19,838)
Repurchase of common stock (in shares)		(320,207)
Exercise of stock options	4,287	50	4,237
Exercise of stock options (in shares)		75,714
Vesting of restricted stock units		1	(1)
Vesting of restricted stock units (in shares)		2,341
Issuances of restricted stock, net of forfeitures		10	(10)
Issuances of restricted stock, net of forfeitures (in shares)		14,980
Tax benefit accrued on stock option exercises / (reversal) associated with stock options	(303)		(303)
Compensation expense on stock options	597		597
Compensation expense on restricted stock and restricted stock units	1,202		1,202
Dividends declared	(14,423)			(14,423)
Net change in unrealized losses on investment securities, available-for-sale, net of tax	(5)				(5)
Balance at Mar. 31, 2012	258,806	5,961	95,971	156,858	16
Balance (in shares) at Mar. 31, 2012	8,942,793	8,942,793
Increase (decrease) in stockholders' equity
Net income	17,454			17,454
Repurchase of common stock	(57,633)	(675)	(56,958)
Repurchase of common stock (in shares)		(1,013,655)
Exercise of stock options	2,160	34	2,126
Exercise of stock options (in shares)		50,505
Vesting of restricted stock units		1	(1)
Vesting of restricted stock units (in shares)		1,743
Issuances of restricted stock, net of forfeitures		(1)	1
Issuances of restricted stock, net of forfeitures (in shares)		(1,184)
Tax benefit accrued on stock option exercises / (reversal) associated with stock options	135		135
Compensation expense on stock options	(106)		(106)
Compensation expense on restricted stock and restricted stock units	290		290
Dividends declared	(16,841)			(16,841)
Net change in unrealized losses on investment securities, available-for-sale, net of tax	(20)				(20)
Balance at Mar. 31, 2013	$ 204,245	$ 5,320	$ 41,458	$ 157,471	$ (4)
Balance (in shares) at Mar. 31, 2013	7,980,202	7,980,202