Income Tax Expense Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate, Continuing Operations	24.00%	34.10%	29.30%	34.40%
Unrecognized Tax Benefits	$ 10,884		$ 10,884		$ 1,527
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	10,599		10,599		1,242
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	10,481		10,481
Income Tax Examination, Interest Accrued	1,305		1,305
Income Tax Examination, Penalties Accrued	$ 64		$ 64