Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 29, 2013	Jun. 30, 2014	Jun. 29, 2013
Income Statement [Abstract]
Net sales	$ 215,198	$ 181,095	$ 425,336	$ 366,245
Cost of sales	148,728	126,676	297,070	256,327
Gross profit	66,470	54,419	128,266	109,918
Operating expenses:
Selling, general and administrative expenses	40,499	32,628	78,761	65,070
Research and development expenses	4,012	3,214	7,901	6,148
Restructuring costs	0	238	0	558
Total operating expenses	44,511	36,080	86,662	71,776
Income from operations	21,959	18,339	41,604	38,142
Other non-operating income and expense:
Interest expense, net	2,972	2,658	5,991	5,263
Other non-operating expense (income), net	225	144	759	97
Total other non-operating income expense, net	3,197	2,802	6,750	5,360
Income before income taxes	18,762	15,537	34,854	32,782
Provision for income taxes	5,944	4,861	10,673	10,247
Net income	12,818	10,676	24,181	22,535
Net (income) loss attributable to non-controlling interest	(21)	13	(19)	34
Net income attributable to Altra Industrial Motion Corp.	$ 12,797	$ 10,689	$ 24,162	$ 22,569
Weighted average shares, basic (in shares)	26,816	26,733	26,823	26,737
Weighted average shares, diluted (in shares)	27,546	26,751	27,647	26,820
Net income per share:
Basic net income attributable to Altra Industrial Motion Corp. (in usd per share)	$ 0.48	$ 0.40	$ 0.90	$ 0.84
Diluted net income attributable to Altra Industrial Motion Corp. (in usd per share)	$ 0.46	$ 0.40	$ 0.87	$ 0.84
Cash dividend declared (in usd per share)	$ 0.12	$ 0.10	$ 0.22	$ 0.18