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           Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (Unaudited) (USD $) 
        In Thousands, unless otherwise specified  | 
        3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
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           Dec. 31, 2012 
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           Dec. 31, 2011 
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           Dec. 31, 2012 
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           Dec. 31, 2011 
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| Condensed Consolidated Statements of Comprehensive Income [Abstract] | ||||
| Defined benefit pension and other postretirement plans, tax | $ 78 | $ 35 | $ 235 | $ 105 | 
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- Definition 
          Tax effect, net of reclassification adjustments, of pension and other postretirement benefit plans (gain) loss included in accumulated other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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