Income Tax Expense Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate, Continuing Operations	33.40%	34.40%
Unrecognized Tax Benefits	$ 1,527
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1,242
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	1,124
Income Tax Examination, Interest Accrued	994
Income Tax Examination, Penalties Accrued	$ 64