CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Apr. 01, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 415,005	$ 395,152
Short-term investments, at cost which approximates market	20,302	18,494
Accounts receivable, net	198,131	194,317
Inventories	89,556	90,760
Prepaid expenses and other current assets	20,531	21,566
Total current assets	743,525	720,289
Property, plant and equipment, less accumulated depreciation and depletion - April 1, 2012- $948,112; December 31, 2011 - $930,515	316,644	318,134
Goodwill	65,788	64,671
Other assets and deferred charges	60,794	61,861
Total assets	1,186,751	1,164,955
Current liabilities:
Short-term debt	5,494	5,846
Current maturities of long-term debt	8,555	8,552
Accounts payable	106,979	103,354
Restructuring liabilities	801	1,411
Other current liabilities	52,650	61,739
Total current liabilities	174,479	180,902
Long-term debt	85,455	85,449
Accrued Pension and Post-Retirement Benefits	98,598	97,318
Other non-current liabilities	30,389	33,266
Total liabilities	388,921	396,935
Shareholders' equity:
Common stock	2,923	2,913
Additional paid-in capital	337,013	335,134
Retained earnings	980,275	963,130
Accumulated other comprehensive income (loss)	(35,312)	(45,331)
Less common stock held in treasury	(514,234)	(514,234)
Total MTI shareholders' equity	770,665	741,612
Non-controlling interest	27,165	26,408
Total shareholders' equity	797,830	768,020
Total liabilities and shareholders' equity	$ 1,186,751	$ 1,164,955