Stock-Based Compensation (Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Stock-based compensation expense related to:
Equity Incentive Plan	$ 3,581	$ 3,528	$ 21,441	$ 19,682
Employee Stock Purchase Plan - options to purchase stock	995	1,024	3,101	3,062
Stock-based compensation expense	4,576	4,552	24,542	22,744
Tax benefit	(1,503)	(1,443)	(8,931)	(7,826)
Stock-based compensation expense, net of tax	$ 3,073	$ 3,109	$ 15,611	$ 14,918