Accumulated Other Comprehensive Income (Loss) Components of Net of Tax (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax [Roll Forward]
Balance as of March 31, 2014	$ (53,923)
Foreign currency translation	2,743	(3,762)
Unrealized net gain on investments	17,298	21
Change in fair value of cash flow hedges	834	6,322
Amount reclassified from AOCI	3,647	4,410
Other comprehensive income (loss)	20,875
Balance as of June 30, 2014	(33,048)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax [Roll Forward]
Balance as of March 31, 2014	(39,287)
Foreign currency translation	2,743
Unrealized net gain on investments
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)	2,743
Balance as of June 30, 2014	(36,544)
Unrealized Net Gain on Investments [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax [Roll Forward]
Balance as of March 31, 2014	5,991
Foreign currency translation
Unrealized net gain on investments	17,298
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)	17,298
Balance as of June 30, 2014	23,289
Fair Market Value of Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax [Roll Forward]
Balance as of March 31, 2014	(20,321)
Foreign currency translation
Unrealized net gain on investments
Change in fair value of cash flow hedges	(2,813)
Amount reclassified from AOCI	3,647
Other comprehensive income (loss)	834
Balance as of June 30, 2014	(19,487)
Postretirement Benefit Obligation Gain [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax [Roll Forward]
Balance as of March 31, 2014	(306)
Foreign currency translation
Unrealized net gain on investments
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)
Balance as of June 30, 2014	$ (306)