Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense related to:
Stock-based compensation expense		$ 13,650	$ 14,830
Tax benefit		(4,964)	(5,509)
Stock-based compensation expense, net of tax		8,686	9,321
Equity Incentive Plan [Member] | Stock Option [Member]
Stock-based compensation expense related to:
Stock-based compensation expense	[1]	12,495	13,772
Employee Stock Purchase Plan [Member] | Stock Option [Member]
Stock-based compensation expense related to:
Stock-based compensation expense		$ 1,155	$ 1,058

[1] Stock-based compensation expense related to stock options granted under the Company’s Equity Incentive Plan is highest during the Company’s fiscal first quarter ended June 30th relative to other quarters during the year. This is primarily due to a retirement-eligible vesting provision under the plan and the timing of the majority of the Company’s stock option awards each year during its fiscal first quarter.