Provisions for Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Pretax earnings:
U.S.	$ 516,207	$ 389,342	$ 302,748
Non-U.S.	21,315	19,145	22,888
Total pretax earnings	537,522	408,487	325,636
Current provision (benefit)
Federal	131,246	116,788	10,899
State	12,641	12,199	5,514
Non-U.S.	3,787	3,344	4,786
Current provision (benefit), total	147,674	132,331	21,199
Deferred provision (benefit)
Federal	37,979	8,466	89,327
State	7,553	1,458	8,310
Non-U.S.	1,925	1,524	1,433
Deferred provision (benefit), total	47,457	11,448	99,070
Provision for income tax expense	195,131	143,779	120,269
Income taxes paid (net of income tax refunds)	$ 138,384	$ 144,682	$ 10,739