Segment Information, Geographic operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 253,057	$ 247,025	$ 743,727	$ 679,379
Long-lived assets	1,195,948		1,195,948		985,381
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	154,857	148,842	475,193	426,738
Long-lived assets	946,653		946,653		944,506
Europe and Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	67,426	64,479	177,756	165,890
Long-lived assets	241,297		241,297		33,037
Other interenational operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	30,774	33,704	90,778	86,751
Long-lived assets	$ 7,998		$ 7,998		$ 7,838