Quarterly Results (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Effect of Fourth Quarter Events [Line Items]
Loss Contingency Accrual , Product Liability, Net, Explanation of Material Change in Accrual									-17403
Sales Revenue, Goods, Net	$ 263,211,000	$ 239,403,000	$ 223,502,000	$ 202,013,000	$ 256,852,000	$ 212,622,000	$ 197,092,000	$ 77,272,000	$ 928,129,000	$ 743,838,000	$ 799,002,000
Sales Revenue, Services, Net	127,038,000	115,812,000	119,205,000	116,626,000	120,908,000	115,661,000	115,333,000	111,708,000	478,681,000	463,610,000	458,731,000
Revenues	390,249,000	355,215,000	342,707,000	318,639,000	377,760,000	328,283,000	312,425,000	188,980,000	1,406,810,000	1,207,448,000	1,257,733,000
Cost of Goods Sold	149,781,000	145,976,000	138,805,000	117,433,000	153,770,000	123,381,000	110,736,000	106,576,000	551,995,000	494,463,000	454,988,000
Cost of Services	76,243,000	71,233,000	70,593,000	68,281,000	67,963,000	67,888,000	66,634,000	64,338,000	286,350,000	266,823,000	263,564,000
Cost of Revenue	226,024,000	217,209,000	209,398,000	185,714,000	221,733,000	191,269,000	177,370,000	170,914,000	838,345,000	761,286,000	718,552,000
Gross Profit	164,225,000	138,006,000	133,309,000	132,925,000	156,027,000	137,014,000	135,055,000	18,066,000	568,465,000	446,162,000	539,181,000
Restructuring Charges	(877,000)	1,164,000	99,000	258,000	779,000	(23,000)	105,000	341,000	644,000	1,202,000	4,848,000
Net Income (Loss) Attributable to Parent	44,171,000	33,649,000	29,564,000	28,731,000	39,000,000	21,765,000	35,711,000	(45,210,000)	136,115,000	51,265,000	128,467,000
Earnings Per Share, Basic	$ 0.77	$ 0.58	$ 0.50	$ 0.48	$ 0.66	$ 0.37	$ 0.60	$ (0.76)	$ 2.33	$ 0.86	$ 2.18
Earnings Per Share, Diluted	$ 0.76	$ 0.58	$ 0.50	$ 0.48	$ 0.65	$ 0.36	$ 0.59	$ (0.76)	$ 2.31	$ 0.85	$ 2.16
Gross profit percentage [Member]
Effect of Fourth Quarter Events [Line Items]
Gross Profit	0.421	0.389	0.389	0.417	0.413	0.417	0.432	0.096
Customer Rebates [Member]
Effect of Fourth Quarter Events [Line Items]
Loss Contingency Accrual , Product Liability, Net, Explanation of Material Change in Accrual									15306
Loss Contingency, Accrual Carrying Value, Current							(102,313,000)
Pending or Threatened Litigation [Member]
Effect of Fourth Quarter Events [Line Items]
Estimated Litigation Liability						19,796,000
Product Disposal [Member]
Effect of Fourth Quarter Events [Line Items]
Loss Contingency Accrual , Product Liability, Net, Explanation of Material Change in Accrual									2097
Loss Contingency, Accrual Carrying Value, Current							$ (7,691,000)