CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 449,106	$ 395,152
Short-term investments, at cost which approximates market	12,700	18,494
Accounts receivable, net	194,240	194,317
Inventories	93,143	90,760
Prepaid expenses and other current assets	21,039	21,566
Total current assets	770,228	720,289
Property, plant and equipment, less accumulated depreciation and depletion - September 30, 2012 - $933,525; December 31, 2011 - $930,515	318,891	318,134
Goodwill	65,738	64,671
Other assets and deferred charges	54,408	61,861
Total assets	1,209,265	1,164,955
Current liabilities:
Short-term debt	5,117	5,846
Current maturities of long-term debt	1,977	8,552
Accounts payable	102,203	103,354
Restructuring liabilities	593	1,411
Other current liabilities	67,108	61,739
Total current liabilities	176,998	180,902
Long-term debt	83,753	85,449
Accrued Pension and Post-Retirement Benefits	90,970	97,318
Other non-current liabilities	29,199	33,266
Total liabilities	380,920	396,935
Shareholders' equity:
Common stock	2,931	2,913
Additional paid-in capital	343,906	335,134
Retained earnings	1,016,851	963,130
Accumulated other comprehensive loss	(37,783)	(45,331)
Less common stock held in treasury	(522,943)	(514,234)
Total MTI shareholders' equity	802,962	741,612
Non-controlling interest	25,383	26,408
Total shareholders' equity	828,345	768,020
Total liabilities and shareholders' equity	$ 1,209,265	$ 1,164,955