Earnings Per Share (EPS) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Basic EPS
Income from continuing operations attributable to MTI	$ 22,000,000	$ 20,200,000	$ 41,600,000	$ 38,800,000
Loss from discontinued operations attributable to MTI	(4,900,000)	(500,000)	(5,700,000)	1,100,000
Net income attributable to MTI	17,120,000	19,715,000	35,876,000	37,747,000
Weighted average shares outstanding (in shares)	34,799,000	35,448,000	34,897,000	35,442,000
Basic earnings per share from continuing operations attributable to MTI (in dollars per share)	$ 0.63	$ 0.57	$ 1.19	$ 1.09
Basic loss per share from discontinued operations attributable to MTI (in dollars per share)	$ (0.14)	$ (0.01)	$ (0.16)	$ 0.03
Basic earnings per share attributable to MTI (in dollars per share)	$ 0.49	$ 0.56	$ 1.03	$ 1.06
Diluted EPS
Income from continuing operations attributable to MTI	22,000,000	20,200,000	41,600,000	38,800,000
Loss from discontinued operations attributable to MTI	(4,900,000)	(500,000)	(5,700,000)	1,100,000
Net income attributable to MTI	$ 17,120,000	$ 19,715,000	$ 35,876,000	$ 37,747,000
Weighted average shares outstanding (in shares)	34,799,000	35,448,000	34,897,000	35,442,000
Dilutive effect of stock options and stock units (in shares)	200,000	100,000	200,000	200,000
Weighted average shares outstanding , adjusted (in shares)	35,031,000	35,580,000	35,141,000	35,590,000
Diluted earnings per share from continuing operations attributable to MTI (in dollars per share)	$ 0.63	$ 0.57	$ 1.18	$ 1.09
Diluted loss per share from discontinued operations attributable to MTI (in dollars per share)	$ (0.14)	$ (0.01)	$ (0.16)	$ 0.03
Diluted earnings per share attributable to MTI (in dollars per share)	$ 0.49	$ 0.56	$ 1.02	$ 1.06
Anti-dilutive options not included in the weighted average common shares outstanding calculation			239,770	305,131