DIVIDENDS, SHARE REPURCHASES AND EARNINGS PER SHARE (TABLES)

6 Months Ended

Sep. 30, 2013

Dividends, Share Repurchases and Earning Per Share [Abstract]

Schedule of antidilutive securities

	Three Months Ended   September 30,				Six Months Ended   September 30,
	2013		2012		2013		2012
Options:
Outstanding	596,191		552,209		497,041		448,269
Weighted average exercise price	$	53.10	$	43.56	$	50.84	$	43.81
Restricted stock units:
Outstanding	—		4,040		—		58,016
Weighted average price	$	—	$	53.89	$	—	$	46.97
Restricted stock awards:
Outstanding	—		—		5,611		—
Weighted average price	$	—	$	—	$	68.31	$	—

Schedule Of Earnings Per Share Basic And Diluted [Table Text Block]

	Three Months Ended   September 30,				Six Months Ended   September 30,
	2013		2012		2013		2012
Net income available to common stockholders (in thousands):
Income available to common stockholders – basic	$	110,606	$	29,668	$	137,492	$	53,330
Interest expense on assumed conversion of 3% Convertible Senior Notes, net of tax (1)	—		—		—		—
Income available to common stockholders – diluted	$	110,606	$	29,668	$	137,492	$	53,330
Shares:
Weighted average number of common shares outstanding – basic	36,403,556		35,815,672		36,265,932		35,858,237
Assumed conversion of 3% Convertible Senior Notes outstanding during the period (1)	—		—		—		—
Net effect of dilutive stock options, restricted stock units and restricted stock awards based on the treasury stock method	297,670		526,620		352,492		601,940
Weighted average number of common shares outstanding – diluted	36,701,226		36,342,292		36,618,424		36,460,177
Basic earnings per common share	$	3.04	$	0.83	$	3.79	$	1.49
Diluted earnings per common share	$	3.01	$	0.82	$	3.75	$	1.46