Segment Information, Geographic operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 227,516	$ 226,161
Long-lived assets	1,102,815		1,106,338
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	141,963	144,844
Long-lived assets	881,760		888,032
Austria [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	203,004		201,224
Europe and Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	51,725	49,374
Other international operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	33,828	31,943
Long-lived assets	$ 18,051		$ 17,082