Consolidated Balance Sheets (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Current Assets
Cash	$ 86,386	$ 44,663
Trade receivables, less allowances for doubtful accounts of $28,650 and $31,845 at March 31, 2013 and 2012, respectively	710,740	652,439
Inventories, net (Note 4)	474,821	408,438
Deferred income tax asset, net (Note 5)	53,562	49,617
Prepaid expenses and other current assets	138,321	119,049
Total current assets	1,463,830	1,274,206
Plant and equipment at cost (Note 6)	4,585,933	4,306,420
Less accumulated depreciation	(1,899,628)	(1,690,361)
Plant and equipment, net	2,686,305	2,616,059
Goodwill (Note 7)	1,195,613	1,163,803
Other intangible assets, net (Note 7)	226,824	214,204
Other non-current assets	45,653	52,313
Total assets	5,618,225	5,320,585
Current Liabilities
Accounts payable, trade	183,258	174,868
Accrued expenses and other current liabilities (Note 8)	374,883	356,344
Short-term debt (Note 9)	0	388,452
Current portion of long-term debt (Note 9)	303,573	10,385
Total current liabilities	861,714	930,049
Long-term debt, excluding current portion (Note 9)	2,304,245	1,761,902
Deferred income tax liability, net (Note 5)	825,612	793,957
Other non-current liabilities	89,671	84,419
Commitments and contingencies (Notes 16 and 17)
Stockholders' Equity (Note 12)
Preferred stock, 20,030 shares authorized, no shares issued or outstanding at March 31, 2013 and 2012	0	0
Common stock, par value $0.01 per share, 200,000 shares authorized, 87,135 and 86,874 shares issued at March 31, 2013 and 2012, respectively	871	869
Capital in excess of par value	729,850	649,551
Retained earnings	1,861,395	1,701,478
Accumulated other comprehensive income	4,438	5,386
Treasury stock, 14,077 and 10,207 shares at cost at March 31, 2013 and 2012, respectively	(1,059,571)	(607,026)
Total stockholders' equity	1,536,983	1,750,258
Total liabilities and stockholders' equity	5,618,225	5,320,585
Allowance for Doubtful Accounts Receivable, Current	$ 28,650	$ 31,845
Preferred stock, shares authorized	20,030,000	20,030,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	87,135,000	86,874,000
Treasury stock, shares	14,077,000	10,207,000