Altra Industrial Motion (AIMC) 10-Q 29 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 28, 2013	Oct. 08, 2013
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	28-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Entity Registrant Name	Altra Holdings, Inc.
Entity Central Index Key	1374535
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		26,968,006

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$70,272	$85,154
Trade receivables, less allowance for doubtful accounts of $2,772 and $2,560 at September 28, 2013 and December 31, 2012, respectively	99,773	92,933
Inventories	120,571	123,776
Deferred income taxes	9,646	8,918
Income tax receivable	867	6,397
Prepaid expenses and other current assets	6,274	6,578
Total current assets	307,403	323,756
Property, plant and equipment, net	136,196	138,094
Intangible assets, net	71,137	76,098
Goodwill	88,115	88,225
Deferred income taxes	1,173	1,150
Other non-current assets, net	4,490	5,716
Total assets	608,514	633,039
Current liabilities:
Accounts payable	47,454	43,042
Accrued payroll	20,277	19,893
Accruals and other current liabilities	33,384	33,796
Deferred income taxes		34
Current portion of long-term debt	12,800	9,135
Total current liabilities	113,915	105,900
Long-term debt-less current portion and net of unaccreted discount	181,085	238,460
Deferred income taxes	39,444	38,821
Pension liabilities	12,048	14,529
Other post retirement benefits	196	230
Long-term taxes payable	1,155	1,118
Other long-term liabilities	720	730
Redeemable non-controlling interest	1,041	1,239
Commitment and Contingencies (See Note 17)
Stockholders' equity:
Common stock ($0.001 par value, 90,000,000 shares authorized, 26,817,671 and 26,724,349 issued and outstanding at September 28, 2013 and December 31, 2012, respectively)	27	27
Additional paid-in capital	153,419	152,188
Retained earnings	128,722	103,200
Accumulated other comprehensive loss	-23,258	-23,403
Total stockholders' equity	258,910	232,012
Total liabilities, non-controlling interest and stockholders' equity	$608,514	$633,039

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$2,772	$2,560
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	26,817,671	26,724,349
Common stock, shares outstanding	26,817,671	26,724,349

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Income Statement [Abstract]
Net sales	$175,443	$174,488	$541,688	$554,816
Cost of sales	121,785	122,477	378,112	390,130
Gross profit	53,658	52,011	163,576	164,686
Operating expenses:
Selling, general and administrative expenses	31,672	30,785	96,742	94,666
Research and development expenses	3,002	2,823	9,150	8,792
Restructuring costs	97		655
Total operating expenses	34,771	33,608	106,547	103,458
Income from operations	18,887	18,403	57,029	61,228
Other non-operating expense:
Interest expense, net	2,567	6,637	7,830	18,915
Other non-operating expense, net	686	402	783	1,834
Total other non-operating expense, net	3,253	7,039	8,613	20,749
Income before income taxes	15,634	11,364	48,416	40,479
Provision for income taxes	5,176	2,846	15,423	10,836
Net income	10,458	8,518	32,993	29,643
Net loss attributable to non-controlling interest	43	29	77	29
Net income attributable to Altra Holdings, Inc.	$10,501	$8,547	$33,070	$29,672
Weighted average shares, basic	26,780	26,675	26,750	26,632
Weighted average shares, diluted	26,836	26,708	26,852	26,737
Net income per share:
Basic net income attributable to Altra Holdings, Inc	$0.39	$0.32	$1.24	$1.11
Diluted net income attributable to Altra Holdings, Inc.	$0.39	$0.32	$1.23	$1.11
Cash dividend declared	$0.10	$0.05	$0.28	$0.10

Condensed_Consolidated_Stateme1

Condensed Consolidated Statement of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$10,458	$8,518	$32,993	$29,643
Other Comprehensive income (loss):
Foreign currency translation adjustment	-6,727	6,605	-46	3,140
Change in fair value of interest rate swap	-346		191
Other comprehensive income (loss)	-7,073	6,605	145	3,140
Comprehensive income	3,385	15,123	33,138	32,783
Comprehensive loss attributable to noncontrolling interest	43	29	77	29
Comprehensive income attributable to Altra Holdings, Inc.	$3,428	$15,152	$33,215	$32,812

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012
Cash flows from operating activities
Net income	$32,993	$29,643
Adjustments to reconcile net income to net cash flows:
Depreciation	16,047	15,038
Amortization of intangible assets	4,882	5,052
Amortization of deferred financing costs	646	1,447
Loss on foreign currency, net	593	44
Accretion of debt discount, net	2,331	2,585
Stock-based compensation	2,397	2,233
Changes in assets and liabilities:
Trade receivables	-8,756	-2,134
Inventories	3,451	3,106
Accounts payable and accrued liabilities	9,197	-557
Other current assets and liabilities	254	984
Other operating assets and liabilities	-1,866	-2,948
Net cash from operating activities	62,169	54,493
Cash flows from investing activities
Purchase of property, plant and equipment	-14,361	-25,162
Net cash from investing activities	-14,361	-32,606
Cash flows from financing activities
Payments on Term Loan Facility	-3,750
Payments on Revolving Credit Facility	-54,304
Purchase of 8 1/8 Senior Secured Notes		-21,000
Proceeds from Equipment and Working Capital Notes	3,550
Payment of Equipment and Working Capital notes	-1,100
Dividend payments	-4,852	-1,348
Redemption of variable rate demand revenue bonds related to the San Marcos facility		-3,000
Shares surrendered for tax withholding	-1,166	-905
Payments on mortgages and other	-515	-736
Payments on capital leases	-25	-303
Net cash from financing activities	-62,162	-27,292
Effect of exchange rate changes on cash and cash equivalents	-528	1,026
Net change in cash and cash equivalents	-14,882	-4,379
Cash and cash equivalents at beginning of year	85,154	92,515
Cash and cash equivalents at end of period	70,272	88,136
Cash paid during the period for:
Interest	5,561	11,848
Income taxes	15,156	8,567
Lamiflex [Member]
Cash flows from investing activities
Acquisition of Lamiflex, net of $68 cash received		($7,444)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2012
Lamiflex [Member]
Cash acquired from acquisition	$68
Senior Secured Notes [Member]
Interest rate on Senior Secured Notes	8.13%

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Redeemable Non-Controlling Interest [Member]
In Thousands
Beginning Balance at Dec. 31, 2011	$208,396	$27	$150,234	$83,211	($25,076)
Beginning Balance, Shares at Dec. 31, 2011		26,600
Stock-based compensation and vesting of restricted stock	1,328		1,328
Stock-based compensation and vesting of restricted stock, Shares		119
Net income attributable to Altra Holdings, Inc.	29,672			29,672
Net loss attributable to non-controlling interest	-29			-29		-29
Fair value of non-controlling interest at acquisition						1,327
Dividends declared	-2,694			-2,694
Cumulative foreign currency translation adjustment	3,140				3,140
Ending Balance at Sep. 29, 2012	239,813	27	151,562	110,160	-21,936	1,298
Ending Balance, Shares at Sep. 29, 2012		26,719
Beginning Balance at Dec. 31, 2012	232,012	27	152,188	103,200	-23,403	1,239
Beginning Balance, Shares at Dec. 31, 2012		26,724
Stock-based compensation and vesting of restricted stock	1,231		1,231
Stock-based compensation and vesting of restricted stock, Shares		94
Net income attributable to Altra Holdings, Inc.	33,070			33,070
Net loss attributable to non-controlling interest	-77			-77		-77
Dividends declared	-7,471			-7,471
Change in fair value of interest rate swap	191				191
Cumulative foreign currency translation adjustment	-46				-46	-121
Ending Balance at Sep. 28, 2013	$258,910	$27	$153,419	$128,722	($23,258)	$1,041
Ending Balance, Shares at Sep. 28, 2013		26,818

Organization_and_Nature_of_Ope

Organization and Nature of Operations	9 Months Ended
	Sep. 28, 2013
Accounting Policies [Abstract]
Organization and Nature of Operations	1. Organization and Nature of Operations
	Headquartered in Braintree, Massachusetts, Altra Holdings, Inc. (the “Company”), through its wholly-owned subsidiary Altra Industrial Motion, Inc. (“Altra Industrial”), is a leading multi-national designer, producer and marketer of a wide range of electro-mechanical power transmission and motion control products. The Company brings together strong brands covering over 50 product lines with production facilities in nine countries and sales coverage in over 70 countries. The Company’s leading brands include Boston Gear, Warner Electric, TB Wood’s, Formsprag Clutch, Ameridrives Couplings, Industrial Clutch, Kilian Manufacturing, Marland Clutch, Nuttall Gear, Stieber Clutch, Wichita Clutch, Twiflex Limited, Bibby Transmissions, Matrix International, Inertia Dynamics, Huco Dynatork, Warner Linear, Bauer Gear Motor, and PowerFlex.

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 28, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	2. Basis of Presentation
	The Company was formed on November 30, 2004 following acquisitions of The Kilian Company (“Kilian”) and certain subsidiaries of Colfax Corporation (“Colfax”). During 2006, the Company acquired Hay Hall Holdings Limited (“Hay Hall”) and Bear Linear. On April 5, 2007, the Company acquired TB Wood’s Corporation (“TB Wood’s”), and on October 5, 2007, the Company acquired substantially all of the assets of All Power Transmission Manufacturing, Inc. On May 29, 2011, the Company acquired substantially all of the assets of Danfoss Bauer GmbH relating to its gear motor business (“Bauer”). On July 11, 2012, the Company acquired 85% of privately held Lamiflex do Brasil Equipamentos Industriais Ltda. (“Lamiflex”).
	The Company’s unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and do not include all of the information and note disclosures required by accounting principles generally accepted in the United States of America. These statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, necessary to present fairly the Company’s financial position as of September 28, 2013 and December 31, 2012, results of operations for the quarter and year to date periods ended September 28, 2013 and September 29, 2012, and cash flows for the year to date periods ended September 28, 2013 and September 29, 2012. The Company follows a four, four, five week calendar per quarter with all quarters consisting of thirteen weeks of operations with the fiscal year end always on December 31.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 28, 2013
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments
	The carrying values of financial instruments, including accounts receivable, cash equivalents, accounts payable, other accrued liabilities, and debt under the Company’s Credit Agreement with certain financial institutions including an initial term loan facility of $100,000,000 (the “Term Loan Facility”) and an initial revolving credit facility of $200,000,000 (the “Revolving Credit Facility”) approximate their fair values due to their variable rate nature at current market rates.
	The carrying amount of the 2.75% Convertible Notes (the “Convertible Notes”) was $85.0 million at each of September 28, 2013 and December 31, 2012. The estimated fair value of the Convertible Notes at September 28, 2013 and December 31, 2012, was $101.0 million and $94.3 million, respectively, based on inputs other than quoted prices that are observable for the Convertible Notes (level 2).
	The estimated fair value of the Company’s interest rate swap agreement with certain financial institutions (“Interest Rate Swap”) at September 28, 2013 was $0.2 million, based on inputs other than quoted prices that are observable for the Interest Rate Swap (level 2). There was no Interest Rate Swap at December 31, 2012.
	Included in cash and cash equivalents as of September 28, 2013 and December 31, 2012 are money market fund investments of $20.4 million and $30.3 million, respectively, which are reported at fair value based on quoted market prices for such investments (level 1).

Changes_in_Accumulated_Other_C

Changes in Accumulated Other Comprehensive Income (Loss) by Component	9 Months Ended
	Sep. 28, 2013
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income (Loss) by Component	4. Changes in Accumulated Other Comprehensive Income (Loss) by Component
	The following is a reconciliation of changes in Accumulated Other Comprehensive Income (Loss) by Component for the periods presented:
		Gains and		Defined			Cumulative			Total
		Losses on		Benefit			Foreign
		Cash Flow		Pension			Currency
		Hedges		Plans			Translation
							Adjustment
	Accumulated Other Comprehensive Income (Loss) by Component, January 1, 2012	$	—	$	(2,485	)	$	(22,591	)	$	(25,076	)
	Net current-period Other Comprehensive Income (Loss)		—		—			3,140			3,140
	Accumulated Other Comprehensive Income (Loss) by Component, September 29, 2012	$	—	$	(2,485	)	$	(19,451	)	$	(21,936	)
		Gains and		Defined			Cumulative			Total
		Losses on		Benefit			Foreign
		Cash Flow		Pension			Currency
		Hedges		Plans			Translation
							Adjustment
	Accumulated Other Comprehensive Income (Loss) by Component, January 1, 2013	$	—	$	(4,607	)	$	(18,796	)	$	(23,403	)
	Net current-period Other Comprehensive Income (Loss)		191		—			(46	)		145
	Accumulated Other Comprehensive Income (Loss) by Component, September 28, 2013	$	191	$	(4,607	)	$	(18,842	)	$	(23,258	)

Net_Income_per_Share

Net Income per Share	9 Months Ended
	Sep. 28, 2013
Earnings Per Share [Abstract]
Net Income per Share	5. Net Income per Share
	Basic earnings per share is based on the weighted average number of shares of common stock outstanding, and diluted earnings per share is based on the weighted average number of shares of common stock outstanding and all potentially dilutive common stock equivalents outstanding. Common stock equivalents are included in the per share calculations when the effect of their inclusion would be dilutive.
	The following is a reconciliation of basic to diluted net income per share:
		Quarter Ended				Year to Date Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
	Net income attributable to Altra Holdings, Inc	$	10,501	$	8,547	$	33,070	$	29,672
	Shares used in net income per common share—basic		26,780		26,675		26,750		26,632
	Incremental shares of unvested restricted common stock		56		33		102		105
	Shares used in net income per common share—diluted		26,836		26,708		26,852		26,737
	Earnings per share:
	Basic net income attributable to Altra Holdings, Inc.	$	0.39	$	0.32	$	1.24	$	1.11
	Diluted net income attributable to Altra Holdings, Inc.	$	0.39	$	0.32	$	1.23	$	1.11
	The Company excluded 2,278,000 shares related to the Convertible Notes (see Note 12) from the above earnings per share calculation as these shares were anti-dilutive.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 28, 2013
Business Combinations [Abstract]
Acquisitions	6. Acquisitions
	In July 2012, the Company consummated an agreement to acquire 85% of privately held Lamiflex do Brasil Equipamentos Industriais Ltda. now known as Lamiflex Do Brasil Equipamentos Industriais S.A. This transaction is known as the Lamiflex Acquisition. The Company acquired 85% of the stock of Lamiflex for 17.4 million Reais ($8.6 million), which was subject to a reduction of 2.1 million Reais ($1.1 million) for estimated net debt at closing.
	The closing date of the Lamiflex Acquisition was July 11, 2012, and as a result, the Company’s condensed consolidated financial statements reflect Lamiflex’s results of operations from the beginning of business on July 11, 2012 forward.
	The Company has completed the valuation of customer relationships, trademarks, deferred tax assets and liabilities and fixed assets and has recorded them as part of its balance sheet.
	The Company recorded a redeemable non-controlling interest from its acquisition of an 85% ownership interest of Lamiflex at fair value at the date of acquisition. In connection with the Lamiflex Acquisition, the Company entered into put and call option agreements with the minority shareholders for the potential purchase of the non-controlling interest at a future date at a value based on a contractually determined formula. As a result of the option agreements, the non-controlling interest is considered redeemable and is classified as temporary equity on the Company’s Condensed Consolidated Balance Sheet.
	The following table sets forth the unaudited pro forma results of operations of the Company for the year to date period ended September 29, 2012, as if the Company had acquired Lamiflex at the beginning of the period. The pro forma information contains the actual operating results of the Company, including Lamiflex, adjusted to include the pro forma impact of (i) additional depreciation expense as a result of estimated depreciation based on the fair value of fixed assets and; (ii) additional expense as a result of the estimated amortization of identifiable intangible assets; These pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisition occurred at the beginning of the period or that may be obtained in the future.
		Pro Forma
		(unaudited)
		Year to Date Period
		Ended
		September 29, 2012
	Total revenues	$	557,527
	Net income attributable to Altra Holdings, Inc.	$	29,989
	Basic earnings per share:
	Net income attributable to Altra Holdings, Inc.	$	1.13
	Diluted earnings per share:
	Net income attributable to Altra Holdings, Inc.	$	1.12

Inventories

Inventories	9 Months Ended
	Sep. 28, 2013
Inventory Disclosure [Abstract]
Inventories	7. Inventories
	Inventories are generally stated at the lower of cost or market, using the first-in, first-out (“FIFO”) method. Market is defined as net realizable value. Inventories located at certain subsidiaries are stated at the lower of cost or market, principally using the last-in, first-out (“LIFO”) method. Inventories at September 28, 2013 and December 31, 2012 consisted of the following:
		September 28,		December 31,
		2013		2012
	Raw materials	$	36,230	$	39,902
	Work in process		18,743		21,199
	Finished goods		65,598		62,675
		$	120,571	$	123,776
	Approximately 9% and 10% of total inventories were valued using the LIFO method as of September 28, 2013 and December 31, 2012, respectively. The Company recorded a $0.1 million provision as a component of cost of sales to value the inventory on a LIFO basis for the quarter ended September 29, 2012. The Company recorded a $0.3 million adjustment as a component of cost of sales to value the inventory on a LIFO basis for the year to date period ended September 29, 2012. There was no provision necessary to value the inventory on a LIFO basis for the quarter or year to date periods ended September 28, 2013.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 28, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	8. Goodwill and Intangible Assets
	Changes to goodwill from January 1, through September 28, 2013 were as follows:
		2013
	Gross goodwill balance as of January 1	$	120,035
	Impact of changes in foreign currency		(110	)
	Gross goodwill balance as of September 28		119,925
	Accumulated impairment as of January 1		(31,810	)
	Impairment charge during the period		—
	Accumulated impairment as of September 28		(31,810	)
	Net goodwill balance September 28, 2013	$	88,115
	Other intangible assets as of September 28, 2013 and December 31, 2012 consisted of the following:
		September 28, 2013					December 31, 2012
		Cost			Accumulated		Cost			Accumulated
					Amortization					Amortization
	Other intangible assets
	Intangible assets not subject to amortization:
	Tradenames and trademarks	$	34,485		$	—	$	34,485		$	—
	Intangible assets subject to amortization:
	Customer relationships		78,864			41,084		78,864			36,202
	Product technology and patents		5,719			5,719		5,719			5,657
	Impact of changes in foreign currency		(1,128	)		—		(1,111	)		—
	Total intangible assets	$	117,940		$	46,803	$	117,957		$	41,859
	The Company recorded $1.7 million and $1.8 million of amortization expense in the quarters ended September 28, 2013 and September 29, 2012, respectively, and recorded $4.9 million and $5.1 million of amortization expense in the year to date periods ended September 28, 2013 and September 29, 2012, respectively.
	The estimated amortization expense for intangible assets is approximately $1.6 million for the remainder of 2013, $6.4 million in each of the next four years and then $9.5 million thereafter.

Warranty_Costs

Warranty Costs	9 Months Ended
	Sep. 28, 2013
Guarantees [Abstract]
Warranty Costs	9. Warranty Costs
	The contractual warranty period generally ranges from three months to two years with a few extending up to thirty-six months based on the product and application of the product. Changes in the carrying amount of accrued product warranty costs for each of the quarters ended September 28, 2013 and September 29, 2012 are as follows:
		September 28,			September 29,
		2013			2012
	Balance at beginning of period	$	5,625		$	4,898
	Accrued current period warranty expense		1,758			1,651
	Payments		(1,743	)		(1,435	)
	Balance at end of period	$	5,640		$	5,114

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 28, 2013
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes
	The estimated effective income tax rates recorded for the year to date periods ended September 28, 2013 and September 29, 2012, were based upon management’s best estimate of the effective tax rate for the entire year.
	The Company and its subsidiaries file a consolidated federal income tax return in the United States as well as consolidated and separate income tax returns in various state and foreign jurisdictions. In the normal course of business, the Company is subject to examination by taxing authorities in all of these jurisdictions. With the exception of certain foreign jurisdictions, the Company is no longer subject to income tax examinations for the tax years prior to 2008.
	Additionally, the Company has indemnification agreements with the sellers of the Bauer and Lamiflex entities that provide for reimbursement to the Company for payments made in satisfaction of tax liabilities relating to pre-acquisition periods.
	The Company recognizes interest and penalties related to unrecognized tax benefits as a component of income tax expense in the condensed consolidated statements of operations. At each of December 31, 2012 and September 28, 2013, the Company had $0.4 million of accrued interest and penalties.

Pension_and_Other_Employee_Ben

Pension and Other Employee Benefits	9 Months Ended
	Sep. 28, 2013
Compensation And Retirement Disclosure [Abstract]
Pension and Other Employee Benefits	11. Pension and Other Employee Benefits
	Defined Benefit (Pension) and Post-retirement Benefit Plans
	The Company sponsors various defined benefit (pension) and post-retirement (medical, dental and life insurance coverage) plans for certain, primarily unionized employees.
	The following table represents the components of the net periodic benefit cost associated with the respective plans for the quarters and year to date periods ended September 28, 2013 and September 29, 2012:
		Quarter Ended
		Pension Benefits						Other Benefits
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
	Service cost	$	37		$	25		$	—		$	1
	Interest cost		246			273			4			3
	Expected return on plan assets		(267	)		(268	)		—			—
	Amortization of net gain		41			25			(13	)		(13	)
	Net periodic benefit cost (income)	$	57		$	55		$	(9	)	$	(9	)
		Year to Date Ended
		Pension Benefits						Other Benefits
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
	Service cost	$	113		$	75		$	2		$	2
	Interest cost		738			819			10			10
	Expected return on plan assets		(801	)		(804	)		—			—
	Amortization of prior service income		—			—			(1	)		(1	)
	Amortization of net gain		125			74			(39	)		(39	)
	Net periodic benefit cost (income)	$	175		$	164		$	(28	)	$	(28	)
	The Company made $3.0 million in contributions during the year to date period ended September 28, 2013.

Debt

Debt	9 Months Ended
	Sep. 28, 2013
Debt Disclosure [Abstract]
Debt	12. Debt
	Outstanding debt obligations at September 28, 2013 and December 31, 2012 were as follows:
		September 28,			December 31,
		2013			2012
	Debt:
	Revolving Credit Facility	$	25,000		$	79,304
	Convertible Notes		85,000			85,000
	Term Notes		96,250			100,000
	Equipment and working capital notes		3,569			1,100
	Mortgages		715			963
	Capital leases		73			99
	Other		253			435
	Total debt		210,860			266,901
	Less: debt discount, net of accretion		(16,975	)		(19,306	)
	Total debt, net of unaccreted discount	$	193,885		$	247,595
	Less current portion of long-term debt		12,800			9,135
	Total long-term debt, net of unaccreted discount	$	181,085		$	238,460
	Credit Agreement
	In November 2012, the Company entered into a Credit Agreement with certain financial institutions (collectively, the “Lenders”), to be guaranteed by certain domestic subsidiaries of the Company (each a “Guarantor” and collectively the “Guarantors”). Pursuant to the Credit Agreement, the Lenders made available to the Company an initial term loan facility of $100,000,000 (the “Term Loan Facility”) and an initial revolving credit facility of $200,000,000 (the “Revolving Credit Facility”).
	Interest on the amounts outstanding under the credit facilities is calculated using either an ABR Rate or Eurodollar rate, plus the applicable margin. The applicable margins for Eurodollar Loans are between 1.375% to 1.875%, and for ABR Loans are between 0.375% and 0.875%. The Credit Agreement provides for a possible expansion of the facilities by an aggregate additional $150,000,000, which can be allocated as additional term loans and/or additional revolving credit loans. The amounts available under the Term Loan Facility and Revolving Credit Facility are to be available for general corporate purposes and to repay existing indebtedness. The stated maturity of both of these credit facilities is November 20, 2017, and there are scheduled quarterly principal payments due on the outstanding amount of the Term Loan Facility. A portion of the Revolving Credit Facility may be used for the issuance of letters of credit, and a portion of the amount of the Revolving Credit Facility is available for borrowings in certain agreed upon foreign currencies.
	The proceeds of the Term Loan Facility and a portion of the proceeds of the Revolving Credit Facility, along with cash on hand, were used by the Company to contribute all funds necessary to redeem all of the Company’s Senior Secured Notes in December 2012 (the “Redemption”). As of September 28, 2013 and December 31, 2012, we had $25.0 and $79.3 million outstanding on our Revolving Credit Facility, respectively. As of September 28, 2013 and December 31, 2012, we had $7.7 and $7.6 million in letters of credit outstanding, respectively. We had $167.3 million and $113.1 million available under the Revolving Credit Facility at September 28, 2013 and December 31, 2012, respectively.
	The Credit Agreement contains various affirmative and negative covenants and restrictions, which among other things, will require the Company and certain Subsidiaries to provide certain financial reports to the Lenders, require the Company to maintain certain financial covenants relating to consolidated leverage and interest coverage, limit maximum annual capital expenditures, and limit the ability of the Company and its subsidiaries to incur or guarantee additional indebtedness, pay dividends or make other equity distributions, purchase or redeem capital stock or debt, make certain investments, sell assets, engage in certain transactions, and effect a consolidation or merger. The Credit Agreement also contains customary events of default.
	Pledge and Security Agreement; Trademark Security Agreement; Patent Security Agreement.
	Pursuant to the Credit Agreement, on November 20, 2012, the Loan Parties and the Administrative Agent entered into a Pledge and Security Agreement (the “Pledge and Security Agreement”), pursuant to which each Loan Party pledges, assigns and grants to the Administrative Agent, on behalf of and for the ratable benefit of the Lenders, a security interest in all of its right, title and interest in, to and under all personal property, whether now owned by or owing to, or after acquired by or arising in favor of such Loan Party (including under any trade name or derivations), and whether owned or consigned by or to, or leased from or to, such Loan Party, and regardless of where located, except for specific excluded personal property identified in the Pledge and Security Agreement (collectively, the “Collateral”). Notwithstanding the foregoing, the Collateral does not include, among other items, more than 65% of the capital stock of the first tier foreign subsidiaries of the Company. The Pledge and Security Agreement contains other customary representations, warranties and covenants of the parties. The Credit Agreement provides that the obligation to grant the security interest can cease upon the obtaining of certain corporate family ratings for the Company, but the obligation to grant a security interest is subject to subsequent reinstatement if the ratings are not maintained as provided in the Credit Agreement.
	In connection with the Pledge and Security Agreement, certain of the Loan Parties delivered a Patent Security Agreement and a Trademark Security Agreement in favor of the Administrative Agent pursuant to which each of the Loan Parties signatory thereto pledges, assigns and grants to the Administrative Agent, on behalf of and for the ratable benefit of the Lenders, a security interest in all of its right, title and interest in, to and under all registered patents, patent applications, registered trademarks and trademark applications owned by such Loan Parties.
	Convertible Senior Notes
	On March 7, 2011, the Company issued $85.0 million of Convertible Senior Notes (the “Convertible Notes”) due on March 1, 2031. The Convertible Notes will mature on March 31, 2031, unless earlier redeemed, repurchased by the Company or converted, and are convertible into cash or shares, or a combination thereof, at the Company’s election. Interest on the Convertible Notes is payable semiannually in arrears, on March 1 and September 1 of each year, and commenced on September 1, 2011 at an annual rate of 2.75%.
	The Company separately accounted for the debt and equity components of the Convertible Notes to reflect the issuer’s non-convertible debt borrowing rate, which interest costs are to be recognized in subsequent periods. The note payable principal balance at the date of issuance of $85.0 million was bifurcated into a debt component of $60.5 million and an equity component of $24.5 million. The difference between the note payable principal balance and the value of the debt component is being accreted to interest expense over the term of the notes. The debt component was recognized at the present value of associated cash flows discounted using a 8.25% discount rate, the borrowing rate at the date of issuance for a similar debt instrument without a conversion feature. The Company paid approximately $3.7 million of issuance costs associated with the Convertible Notes. The Company recorded $1.0 million of debt issuance costs as an offset to additional paid-in capital. The balance of $2.7 million of debt issuance costs is classified as other non-current assets and will be amortized over the term of the notes using the effective interest method.
	The carrying amount of the principal amount of the liability component, the unamortized discount, and the net carrying amount are as follows as of September 28, 2013:
		September 28,
		2013
	Principal amount of debt	$	85,000
	Unamortized discount		16,975
	Carrying value of debt	$	68,025
	Interest expense associated with the Convertible Notes consisted of the following for the year to date period ended September 28, 2013:
		September 28,
		2013
	Contractual coupon rate of interest	$	1,753
	Accretion of Convertible Notes discount and amortization of deferred financing costs		2,594
	Interest expense for the convertible notes	$	4,347
	The effective interest yield of the Convertible Notes due in 2031 is 8.5% at September 28, 2013 and the cash coupon interest rate is 2.75%.
	Senior Secured Notes
	In November 2009, the Company issued 8 1/8% Senior Secured Notes (the “Senior Secured Notes”) with a face value of $210 million. Interest on the Senior Secured Notes was payable semi-annually in arrears, on June 1 and December 1 of each year, commencing on June 1, 2010 at an annual rate of 8 1/8%. The effective interest rate of the Senior Secured Notes was approximately 8.75% after consideration of the $6.7 million of deferred financing costs (included in other non-current assets which are being amortized over the term using the effective interest method). The principal balance of the Senior Secured Notes was scheduled to mature on December 1, 2016.
	The Senior Secured Notes were guaranteed by the Company’s U.S. domestic subsidiaries and were secured by a second priority lien, subject to first priority liens securing the Old Revolving Credit Agreement, on substantially all of the Company’s assets and those of its domestic subsidiaries. The indenture governing the Senior Secured Notes contained covenants which restricted the Company and its subsidiaries. These restrictions limited or prohibited, among other things, the Company’s ability to incur additional indebtedness; repay subordinated indebtedness prior to stated maturities; pay cash dividends on or redeem or repurchase stock or make other distributions; make investments or acquisitions; sell certain assets or merge with or into other companies; sell stock in our subsidiaries; and create liens on their assets. There are no financial covenants associated with the Senior Secured Notes.
	During 2012, Altra Industrial retired the remaining principal balance of the 8 1/8% Senior Secured Notes, of $198.0 million.
	Old Revolving Credit Agreement
	Prior to entering into the current Credit Agreement, Altra Industrial had previously entered into a senior secured credit facility, (the “Old Revolving Credit Agreement”), that provided for borrowing capacity in an initial amount of up to $65.0 million (subject to adjustment pursuant to a borrowing base and subject to increase from time to time in accordance with the terms of the credit facility).
	The Old Revolving Credit Agreement was replaced with the new Revolving Credit Facility in November 2012.
	Equipment and Working Capital Notes
	The Company entered into a 24.6 million RMB ($3.9 million) loan with a bank to equip its new facility in Changzhou, China during 2012. The loan had a remaining principal balance of 7.0 million RMB ($1.1 million) at December 31, 2012. The note was refinanced in an amount of approximately 6.5 million RMB ($1.1 million) during the quarter ended September 28, 2013 with a new bank. The note is due in installments from July through September 2014, when the note expires. Interest is payable monthly at 5.04%.
	The Company entered into a 15.4 million RMB ($2.5 million) loan with a bank to equip its new facility in Changzhou, China during the quarter ended September 28, 2013. The loan has a remaining principal balance of 15.4 million RMB ($2.5 million) at September 28, 2013. The note is due in in installments between June and August of 2016, when the note expires. Interest is payable monthly at 5.54%. The note is callable by the bank at its discretion and as such, has been included in the current portion of long-term debt in the balance sheet at September 28, 2013.
	Mortgage
	The Company has a mortgage with a bank on its facility in Heidelberg, Germany with an interest rate of 2.9% and is payable in monthly installments over the next three years. As of September 28, 2013 and December 31, 2012, the mortgage had a remaining principal balance of €0.5 million or $0.7 million and €0.7 million or $1.0 million, respectively.
	Capital Leases
	The Company leases certain equipment under capital lease arrangements, whose obligations are included in both short-term and long-term debt. Capital lease obligations amounted to approximately $0.1 million at September 28, 2013 and December 31, 2012. Assets subject to capital leases are included in property, plant and equipment with the related amortization recorded as depreciation expense.
	Overdraft Agreements
	Certain of our foreign subsidiaries maintain overdraft agreements with financial institutions. There were no borrowings as of September 28, 2013 or December 31, 2012 under any of the overdraft agreements.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 28, 2013
Equity [Abstract]
Stockholders' Equity	13. Stockholders’ Equity
	The Company declared dividends of $0.10 per share of common stock for the year to date period ended September 29, 2012. The Company declared a cash dividend of $0.05 per share for the quarter ended September 29, 2012. The dividend of $1.3 million was paid on October 2, 2012 to shareholders of record as of the close of business on September 18, 2012 and was accrued for in the balance sheet at September 29, 2012.
	The Company declared dividends of $0.28 per share of common stock for the year to date period ended September 28, 2013. The Company declared a cash dividend of $0.10 per share for the quarter ended September 28, 2013. The dividend of $2.7 million, paid on October 2, 2013, was accrued for in the balance sheet at September 28, 2013.
	Future declarations of quarterly cash dividends are subject to approval by the Board of Directors and to the Board’s continuing determination that the declaration of dividends are in the best interest of the Company’s stockholders and are in compliance with all laws and agreements of the Company applicable to the declaration and payment of cash dividends.
	Stock-Based Compensation
	The Company’s Board of Directors established the 2004 Equity Incentive Plan (as amended, the “Plan”) that provides for various forms of stock-based compensation to independent directors, officers and senior-level employees of the Company. The restricted shares of common stock issued pursuant to the Plan generally vest ratably over a period ranging from immediately to 5 years, provided that the vesting of the restricted shares may accelerate upon the occurrence of certain liquidity events, if approved by the Board of Directors in connection with the transactions. Common stock awarded under the Plan is generally subject to restrictions on transfer, repurchase rights, and other limitations and rights as set forth in the applicable award agreements. The shares are valued based on the share price on the date of grant.
	The Plan permits the Company to grant restricted stock, among other things, to key employees and other persons who make significant contributions to the success of the Company. The restrictions and vesting schedule for restricted stock granted under the Plan are determined by the Personnel and Compensation Committee of the Board of Directors.
	The Plan also permits the Company to grant performance share awards, among other things, to the Company’s executives and certain other officers and employees based on pre-established annual performance objectives and goals. The company issued performance share unit awards during February 2013 and has accrued compensation expense based on the probable outcome of these annual objectives and goals.
	Stock-based compensation expense recorded during the year to date periods ended September 28, 2013 and September 29, 2012, was $2.4 million and $2.2 million, respectively. Stock-based compensation expense recorded during the quarters ended September 28, 2013 and September 29, 2012, was $0.6 million and $0.7 million, respectively. Stock-based compensation has been recorded as an adjustment to selling, general and administrative expenses in the accompanying condensed consolidated statements of operations. The Company recognizes stock-based compensation expense on a straight line basis for the shares vesting ratably under the plan and uses the graded-vesting method of recognizing stock-based compensation expense for the performance share awards based on the probability of the specific performance metrics being achieved over the requisite service period.
	The following table sets forth the activity of the Company’s unvested restricted stock grants in the year to date period ended September 28, 2013:
					Weighted-average
		Shares			grant date fair value
	Restricted shares unvested January 1, 2013		162,586		$	18.67
	Shares granted		127,326			24.53
	Shares vested		(139,577	)		21.5
	Restricted shares unvested September 28, 2013		150,335		$	22.95
	Total remaining unrecognized compensation cost was $3.6 million as of September 28, 2013, which will be recognized over a weighted average remaining period of three years. The fair market value of the shares for which the restrictions have lapsed during the year to date period ended September 28, 2013 was $3.5 million. Restricted shares granted are valued based on the fair market value of the stock on the date of grant.

Derivative_Financial_Instrumen

Derivative Financial Instruments

9 Months Ended

Sep. 28, 2013

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

14. Derivative Financial Instruments

Interest Rate Swap

During the quarter ended June 29, 2013, the Company entered an interest rate swap agreement designed to fix the variable interest rate payable on $98.1 million of its outstanding borrowings under the Credit Agreement at 0.626% exclusive of the credit spread under the Credit Agreement.

The interest rate swap agreement was designed to manage exposure to interest rates on the Company’s variable rate indebtedness. The Company recognizes all derivatives on its balance sheet at fair value. The Company has designated its interest rate swap agreement, which is forward-dated, as a cash flow hedge. Changes in the fair value of the swap are recognized in other comprehensive income until the hedged items are recognized in earnings. Hedge ineffectiveness, if any, associated with the swap will be reported by the Company in interest expense. There was no ineffectiveness associated with the swap during the quarter or year to date periods ended September 28, 2013, nor was any amount excluded from ineffectiveness testing for these periods.

The fair value of the swap recognized in other long-term assets and in other comprehensive income (loss) is as follows (in thousands):

Fixed Rate,

before

Fair Value

Effective Date

Notional

applicable

Maturity

September 28,

December 31,

Amount

Margin

2013

2012

April 30, 2013

$

98,125

0.626

%

November 30, 2016

$

191

$

—

Concentrations_of_Credit_Segme

Concentrations of Credit, Segment Data and Workforce	9 Months Ended
	Sep. 28, 2013
Segment Reporting [Abstract]
Concentrations of Credit, Segment Data and Workforce	15. Concentrations of Credit, Segment Data and Workforce
	Financial instruments, which are potentially subject to counter party performance and concentrations of credit risk, consist primarily of trade accounts receivable. The Company manages these risks by conducting credit evaluations of customers prior to delivery or commencement of services. When the Company enters into a sales contract, collateral is normally not required from the customer. Payments are typically due within thirty days of billing. An allowance for potential credit losses is maintained, and losses have historically been within management’s expectations. No customer represented greater than 10% of total sales for each of the quarters or year to date periods ended September 28, 2013 and September 29, 2012.
	The Company is also subject to counter party performance risk of loss in the event of non-performance by counterparties to financial instruments, such as cash and investments. Cash and investments are held by well-established financial institutions and invested in AAA rated mutual funds or United States Government Securities. The Company is exposed to swap counterparty credit risk with financial institutions. The Company’s counterparty is a well-established financial institution.
	The Company has three operating segments that are regularly reviewed by our chief operating decision maker. Each of these operating segments represents a unit that produces mechanical power transmission products. The Company aggregates all of the operating segments into one reportable segment. The three operating segments are expected to have similar long-term average gross profit margins. All of our products are sold by one global sales force and we have one global marketing function with the exception of the Bauer gear motor business for which the Company is in the process of integrating sales and marketing activities. Strategic markets and industries are determined for the entire company and then targeted by the brands. All of our operating segments have common manufacturing and production processes. Each operating segment includes a machine shop which uses similar equipment and manufacturing techniques. Each of our operating segments uses common raw materials, such as aluminum, steel and copper. The materials are purchased and procurement contracts are negotiated by one global purchasing function.
	The Company serves the general industrial market by selling to original equipment manufacturers (“OEM”) and distributors. Our OEM and distributor customers serve the general industrial market. Resource allocation decisions such as capital expenditure requirements and headcount requirements are made at a consolidated level and allocated to the individual operating segments.
	Discrete financial information is not available by product line at the level necessary for management to assess performance or make resource allocation decisions.
	Net sales to third parties by geographic region are as follows:
		Net Sales				Net Sales
		Quarter Ended				Year to Date Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
	North America (primarily U.S.)	$	109,810	$	112,708	$	343,844	$	358,719
	Europe		52,315		49,832		160,895		162,356
	Asia and other		13,318		11,948		36,949		33,741
	Total	$	175,443	$	174,488	$	541,688	$	554,816
	Net sales to third parties are attributed to the geographic regions based on the country in which the shipment originates.
	The net assets of the Company’s foreign subsidiaries at September 28, 2013 and December 31, 2012 were $128.5 million and $117.0 million, respectively.

Restructuring

Restructuring	9 Months Ended
	Sep. 28, 2013
Restructuring And Related Activities [Abstract]
Restructuring	16. Restructuring
	In the quarter ended December 31, 2012, the Company adopted a restructuring plan (“2012 Altra Plan”) as a result of continued sluggish demand in Europe and general global economic conditions. The actions included in the 2012 Altra Plan include reducing headcount and limiting discretionary spending to improve profitability in Europe. The Company recorded $0.1 million and $0.7 million in restructuring charges associated with the 2012 Altra Plan in the quarter and year to date periods ended September 28, 2013, respectively. The costs were primarily severance charges due in connection with the reduction of the workforce at our European locations.
	The Company’s total restructuring expense, by major component for the year to date period ended September 28, 2013 was as follows:
		Quarter			Year to Date
		Ended			Ended
		September 28,			September 28,
		2013			2013
		2012			2012
		Altra Plan			Altra Plan
	Severance	$	137		$	653
	Other		(40	)		2
	Total cash expenses	$	97		$	655
	The following is a reconciliation of the accrued restructuring costs between December 31, 2012 and September 28, 2013
		All Plans
	Balance at January 1, 2013	$	2,920
	Restructuring expense incurred		655
	Cash payments		(3,293	)
	Balance at September 28, 2013	$	282
	The total restructuring reserve as of September 28, 2013 relates to severance costs to be paid to employees and is recorded in accruals and other current liabilities on the consolidated balance sheet. The Company expects to incur approximately $0.3 to $0.6 million in restructuring expenses during the remainder of 2013 under the 2012 Altra Plan.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 28, 2013
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies
	General Litigation
	The Company is involved in various pending legal proceedings arising out of the ordinary course of business. These proceedings primarily involve commercial claims, product liability claims, personal injury claims, and workers’ compensation claims. None of these legal proceedings are expected to have a material adverse effect on the results of operations, cash flows, or financial condition of the Company. With respect to these proceedings, management believes that the Company will prevail, has adequate insurance coverage or has established appropriate reserves to cover potential liabilities. Any costs that management estimates may be paid related to these proceedings or claims are accrued when the liability is considered probable and the amount can be reasonably estimated. There can be no assurance, however, as to the ultimate outcome of any of these matters, and if all or substantially all of these legal proceedings were to be determined adversely to the Company, there could be a material adverse effect on the results of operations, cash flows, or financial condition of the Company. We have established loss provisions for matters in which losses are probable and can be reasonably estimated. There were no material amounts accrued in the accompanying condensed consolidated balance sheets for potential litigation as of September 28, 2013 or December 31, 2012. For matters where a reserve has not been established and for which we believe a loss is reasonably possible, as well as for matters where a reserve has been recorded but for which an exposure to loss in excess of the amount accrued is reasonably possible, we believe that such losses, individually and in the aggregate, will not have a material effect on our consolidated financial statements.
	The Company also risks exposure to product liability claims in connection with products it has sold and those sold by businesses that the Company acquired. Although in some cases third parties have retained responsibility for product liability claims relating to products manufactured or sold prior to the acquisition of the relevant business and in other cases the persons from whom the Company has acquired a business may be required to indemnify the Company for certain product liability claims subject to certain caps or limitations on indemnification, the Company cannot assure that those third parties will in fact satisfy their obligations with respect to liabilities retained by them or their indemnification obligations. If those third parties become unable to or otherwise do not comply with their respective obligations including indemnity obligations, or if certain product liability claims for which the Company is obligated were not retained by third parties or are not subject to these indemnities, the Company could become subject to significant liabilities or other adverse consequences. Moreover, even in cases where third parties retain responsibility for product liability claims or are required to indemnify the Company, significant claims arising from products that have been acquired could have a material adverse effect on the Company’s ability to realize the benefits from an acquisition, could result in the reduction of the value of goodwill that the Company recorded in connection with an acquisition, or could otherwise have a material adverse effect on the Company’s business, financial condition, or operations.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 28, 2013
Subsequent Events [Abstract]
Subsequent Events	18. Subsequent Events
	The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure.
	The Company made a voluntary $2.0 million pension contribution in October 2013.
	On October 29, 2013, the Company declared a dividend of $0.10 per share for the quarter ended December 31, 2013, payable on January 3, 2014 to shareholders of record as of December 18, 2013.

Changes_in_Accumulated_Other_C1

Changes in Accumulated Other Comprehensive Income (Loss) by Component (Tables)	9 Months Ended
	Sep. 28, 2013
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income (Loss) by Component	The following is a reconciliation of changes in Accumulated Other Comprehensive Income (Loss) by Component for the periods presented:
		Gains and		Defined			Cumulative			Total
		Losses on		Benefit			Foreign
		Cash Flow		Pension			Currency
		Hedges		Plans			Translation
							Adjustment
	Accumulated Other Comprehensive Income (Loss) by Component, January 1, 2012	$	—	$	(2,485	)	$	(22,591	)	$	(25,076	)
	Net current-period Other Comprehensive Income (Loss)		—		—			3,140			3,140
	Accumulated Other Comprehensive Income (Loss) by Component, September 29, 2012	$	—	$	(2,485	)	$	(19,451	)	$	(21,936	)
		Gains and		Defined			Cumulative			Total
		Losses on		Benefit			Foreign
		Cash Flow		Pension			Currency
		Hedges		Plans			Translation
							Adjustment
	Accumulated Other Comprehensive Income (Loss) by Component, January 1, 2013	$	—	$	(4,607	)	$	(18,796	)	$	(23,403	)
	Net current-period Other Comprehensive Income (Loss)		191		—			(46	)		145
	Accumulated Other Comprehensive Income (Loss) by Component, September 28, 2013	$	191	$	(4,607	)	$	(18,842	)	$	(23,258	)

Net_Income_per_Share_Tables

Net Income per Share (Tables)	9 Months Ended
	Sep. 28, 2013
Earnings Per Share [Abstract]
Reconciliation of Basic to Diluted Net Income Per Share	The following is a reconciliation of basic to diluted net income per share:
		Quarter Ended				Year to Date Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
	Net income attributable to Altra Holdings, Inc	$	10,501	$	8,547	$	33,070	$	29,672
	Shares used in net income per common share—basic		26,780		26,675		26,750		26,632
	Incremental shares of unvested restricted common stock		56		33		102		105
	Shares used in net income per common share—diluted		26,836		26,708		26,852		26,737
	Earnings per share:
	Basic net income attributable to Altra Holdings, Inc.	$	0.39	$	0.32	$	1.24	$	1.11
	Diluted net income attributable to Altra Holdings, Inc.	$	0.39	$	0.32	$	1.23	$	1.11

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 28, 2013
Business Combinations [Abstract]
Proforma Amount on Acquisition Occurred	These pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisition occurred at the beginning of the period or that may be obtained in the future.
		Pro Forma
		(unaudited)
		Year to Date Period
		Ended
		September 29, 2012
	Total revenues	$	557,527
	Net income attributable to Altra Holdings, Inc.	$	29,989
	Basic earnings per share:
	Net income attributable to Altra Holdings, Inc.	$	1.13
	Diluted earnings per share:
	Net income attributable to Altra Holdings, Inc.	$	1.12

Inventories_Tables

Inventories (Tables)	9 Months Ended
	Sep. 28, 2013
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories at September 28, 2013 and December 31, 2012 consisted of the following:
		September 28,		December 31,
		2013		2012
	Raw materials	$	36,230	$	39,902
	Work in process		18,743		21,199
	Finished goods		65,598		62,675
		$	120,571	$	123,776

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 28, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Changes in Goodwill	Changes to goodwill from January 1, through September 28, 2013 were as follows:
		2013
	Gross goodwill balance as of January 1	$	120,035
	Impact of changes in foreign currency		(110	)
	Gross goodwill balance as of September 28		119,925
	Accumulated impairment as of January 1		(31,810	)
	Impairment charge during the period		—
	Accumulated impairment as of September 28		(31,810	)
	Net goodwill balance September 28, 2013	$	88,115
Other Intangible Assets	Other intangible assets as of September 28, 2013 and December 31, 2012 consisted of the following:
		September 28, 2013					December 31, 2012
		Cost			Accumulated		Cost			Accumulated
					Amortization					Amortization
	Other intangible assets
	Intangible assets not subject to amortization:
	Tradenames and trademarks	$	34,485		$	—	$	34,485		$	—
	Intangible assets subject to amortization:
	Customer relationships		78,864			41,084		78,864			36,202
	Product technology and patents		5,719			5,719		5,719			5,657
	Impact of changes in foreign currency		(1,128	)		—		(1,111	)		—
	Total intangible assets	$	117,940		$	46,803	$	117,957		$	41,859

Warranty_Costs_Tables

Warranty Costs (Tables)	9 Months Ended
	Sep. 28, 2013
Guarantees [Abstract]
Changes in Carrying Amount of Accrued Product Warranty Costs	Changes in the carrying amount of accrued product warranty costs for each of the quarters ended September 28, 2013 and September 29, 2012 are as follows:
		September 28,			September 29,
		2013			2012
	Balance at beginning of period	$	5,625		$	4,898
	Accrued current period warranty expense		1,758			1,651
	Payments		(1,743	)		(1,435	)
	Balance at end of period	$	5,640		$	5,114

Pension_and_Other_Employee_Ben1

Pension and Other Employee Benefits (Tables)	9 Months Ended
	Sep. 28, 2013
Compensation And Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost	The following table represents the components of the net periodic benefit cost associated with the respective plans for the quarters and year to date periods ended September 28, 2013 and September 29, 2012:
		Quarter Ended
		Pension Benefits						Other Benefits
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
	Service cost	$	37		$	25		$	—		$	1
	Interest cost		246			273			4			3
	Expected return on plan assets		(267	)		(268	)		—			—
	Amortization of net gain		41			25			(13	)		(13	)
	Net periodic benefit cost (income)	$	57		$	55		$	(9	)	$	(9	)
		Year to Date Ended
		Pension Benefits						Other Benefits
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
	Service cost	$	113		$	75		$	2		$	2
	Interest cost		738			819			10			10
	Expected return on plan assets		(801	)		(804	)		—			—
	Amortization of prior service income		—			—			(1	)		(1	)
	Amortization of net gain		125			74			(39	)		(39	)
	Net periodic benefit cost (income)	$	175		$	164		$	(28	)	$	(28	)

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 28, 2013
Debt Disclosure [Abstract]
Outstanding Debt Obligations	Outstanding debt obligations at September 28, 2013 and December 31, 2012 were as follows:
		September 28,			December 31,
		2013			2012
	Debt:
	Revolving Credit Facility	$	25,000		$	79,304
	Convertible Notes		85,000			85,000
	Term Notes		96,250			100,000
	Equipment and working capital notes		3,569			1,100
	Mortgages		715			963
	Capital leases		73			99
	Other		253			435
	Total debt		210,860			266,901
	Less: debt discount, net of accretion		(16,975	)		(19,306	)
	Total debt, net of unaccreted discount	$	193,885		$	247,595
	Less current portion of long-term debt		12,800			9,135
	Total long-term debt, net of unaccreted discount	$	181,085		$	238,460
Carrying Amount of Debt	The carrying amount of the principal amount of the liability component, the unamortized discount, and the net carrying amount are as follows as of September 28, 2013:
		September 28,
		2013
	Principal amount of debt	$	85,000
	Unamortized discount		16,975
	Carrying value of debt	$	68,025
Interest Expense Associated with Convertible Notes	Interest expense associated with the Convertible Notes consisted of the following for the year to date period ended September 28, 2013:
		September 28,
		2013
	Contractual coupon rate of interest	$	1,753
	Accretion of Convertible Notes discount and amortization of deferred financing costs		2,594
	Interest expense for the convertible notes	$	4,347

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 28, 2013
Equity [Abstract]
Company's Unvested Restricted Stock Grants	The following table sets forth the activity of the Company’s unvested restricted stock grants in the year to date period ended September 28, 2013:
					Weighted-average
		Shares			grant date fair value
	Restricted shares unvested January 1, 2013		162,586		$	18.67
	Shares granted		127,326			24.53
	Shares vested		(139,577	)		21.5
	Restricted shares unvested September 28, 2013		150,335		$	22.95

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)

9 Months Ended

Sep. 28, 2013

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Summary of Swaps Recognized in Other Long-term Assets and in Other Comprehensive Income (Loss)

The fair value of the swap recognized in other long-term assets and in other comprehensive income (loss) is as follows (in thousands):

Fixed Rate,

before

Fair Value

Effective Date

Notional

applicable

Maturity

September 28,

December 31,

Amount

Margin

2013

2012

April 30, 2013

$

98,125

0.626

%

November 30, 2016

$

191

$

—

Concentrations_of_Credit_Segme1

Concentrations of Credit, Segment Data and Workforce (Tables)	9 Months Ended
	Sep. 28, 2013
Segment Reporting [Abstract]
Net Sales to Third Parties by Geographic Region	Net sales to third parties by geographic region are as follows:
		Net Sales				Net Sales
		Quarter Ended				Year to Date Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
	North America (primarily U.S.)	$	109,810	$	112,708	$	343,844	$	358,719
	Europe		52,315		49,832		160,895		162,356
	Asia and other		13,318		11,948		36,949		33,741
	Total	$	175,443	$	174,488	$	541,688	$	554,816

Restructuring_Tables

Restructuring (Tables)	9 Months Ended
	Sep. 28, 2013
Restructuring And Related Activities [Abstract]
Summary of Total Restructuring Expense	The Company’s total restructuring expense, by major component for the year to date period ended September 28, 2013 was as follows:
		Quarter			Year to Date
		Ended			Ended
		September 28,			September 28,
		2013			2013
		2012			2012
		Altra Plan			Altra Plan
	Severance	$	137		$	653
	Other		(40	)		2
	Total cash expenses	$	97		$	655
Reconciliation of Accrued Restructuring Costs	The following is a reconciliation of the accrued restructuring costs between December 31, 2012 and September 28, 2013
		All Plans
	Balance at January 1, 2013	$	2,920
	Restructuring expense incurred		655
	Cash payments		(3,293	)
	Balance at September 28, 2013	$	282

Organization_and_Nature_of_Ope1

Organization and Nature of Operations - Additional Information (Detail)	9 Months Ended
	Sep. 28, 2013
	Country
	Product
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of product lines	50
Production facilities in number of countries	9
Sales coverage in number of countries	70

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail)	Jul. 11, 2012
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Percentage of ownership acquired	85.00%

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 28, 2013	Dec. 31, 2012
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Estimated fair value of Interest rate swap	$200,000	$0
Money Market Funds [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and cash equivalents	20,400,000	30,300,000
Term Loan Facility [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Fair value, debt instrument	100,000,000
Revolving Credit Facility [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Fair value, debt instrument	200,000,000
Convertible Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Interest on notes	2.75%	2.75%
Carrying amount of financial instruments	85,000,000	85,000,000
Estimated fair value of financial instruments	$101,000,000	$94,300,000

Changes_in_Accumulated_Other_C2

Changes in Accumulated Other Comprehensive Income (Loss) by Component - Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) by Component, Beginning balance			($23,403)	($25,076)
Net current-period Other Comprehensive Income (Loss)	-7,073	6,605	145	3,140
Accumulated Other Comprehensive Income (Loss) by Component, Ending balance	-23,258	-21,936	-23,258	-21,936
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) by Component, Beginning balance
Net current-period Other Comprehensive Income (Loss)			191
Accumulated Other Comprehensive Income (Loss) by Component, Ending balance	191		191
Defined Benefit Pensions Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) by Component, Beginning balance			-4,607	-2,485
Net current-period Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) by Component, Ending balance	-4,607	-2,485	-4,607	-2,485
Cumulative Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) by Component, Beginning balance			-18,796	-22,591
Net current-period Other Comprehensive Income (Loss)			-46	3,140
Accumulated Other Comprehensive Income (Loss) by Component, Ending balance	($18,842)	($19,451)	($18,842)	($19,451)

Net_Income_per_Share_Reconcili

Net Income per Share - Reconciliation of Basic to Diluted Net Income Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Earnings Per Share [Abstract]
Net income attributable to Altra Holdings, Inc	$10,501	$8,547	$33,070	$29,672
Shares used in net income per common share-basic	26,780	26,675	26,750	26,632
Incremental shares of unvested restricted common stock	56	33	102	105
Shares used in net income per common share-diluted	26,836	26,708	26,852	26,737
Earnings per share:
Basic net income attributable to Altra Holdings, Inc.	$0.39	$0.32	$1.24	$1.11
Diluted net income attributable to Altra Holdings, Inc.	$0.39	$0.32	$1.23	$1.11

Net_Income_per_Share_Additiona

Net Income per Share - Additional Information (Detail)	9 Months Ended
	Sep. 28, 2013
Earnings Per Share [Abstract]
Anti-dilutive shares	2,278,000

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (Lamiflex [Member])	1 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2012	Sep. 28, 2013
	USD ($)	BRL
Business Acquisition [Line Items]
Percentage of acquisition completed	85.00%	85.00%
Business acquisition cost	$8.60	17.4
Estimated business acquisition reduction	$1.10	2.1
Business acquisition date			11-Jul-12

Acquisitions_Proforma_Amount_o

Acquisitions - Proforma Amount on Acquisition Occurred (Detail) (USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 29, 2012
Business Combinations [Abstract]
Total revenues	$557,527
Net income attributable to Altra Holdings, Inc.	$29,989
Basic earnings per share:
Net income attributable to Altra Holdings, Inc.	$1.13
Diluted earnings per share:
Net income attributable to Altra Holdings, Inc.	$1.12

Inventories_Summary_of_Invento

Inventories - Summary of Inventories (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$36,230	$39,902
Work in process	18,743	21,199
Finished goods	65,598	62,675
Inventories	$120,571	$123,776

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
In Millions, unless otherwise specified	Inventory Valuation by LIFO Method [Member]	Inventory Valuation by LIFO Method [Member]	Inventory Valuation Provision [Member]	Inventory Valuation Provision [Member]	Inventory Valuation Provision [Member]	Inventory Valuation Provision [Member]
Inventory [Line Items]
Portion of total inventory valued by LIFO method	9.00%	10.00%
Provision for valuation of sales component			$0	$0.10	$0	$0.30

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Changes in Goodwill (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Dec. 31, 2012
Goodwill And Intangible Assets Disclosure [Abstract]
Gross goodwill balance as of January 1	$120,035
Impact of changes in foreign currency	-110
Gross goodwill balance as of September 28	119,925
Accumulated impairment as of January 1	-31,810
Impairment charge during the period
Accumulated impairment as of September 28	-31,810
Net goodwill balance September 28, 2013	$88,115	$88,225

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Other Intangible Assets (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Intangible Assets [Member]
Other Intangible Assets [Line Items]
Cost of Intangible Assets	$117,940	$117,957
Accumulated Amortization	46,803	41,859
Intangible Assets not Subject to Amortization [Member] | Tradenames and Trademarks [Member]
Other Intangible Assets [Line Items]
Cost of Intangible Assets	34,485	34,485
Intangible Assets Subject to Amortization [Member] | Customer Relationships [Member]
Other Intangible Assets [Line Items]
Cost of Intangible Assets	78,864	78,864
Accumulated Amortization	41,084	36,202
Intangible Assets Subject to Amortization [Member] | Product Technology and Patents [Member]
Other Intangible Assets [Line Items]
Cost of Intangible Assets	5,719	5,719
Accumulated Amortization	5,719	5,657
Intangible Assets Subject to Amortization [Member] | Impact of Changes in Foreign Currency [Member]
Other Intangible Assets [Line Items]
Cost of Intangible Assets	-1,128	-1,111
Accumulated Amortization

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Goodwill And Intangible Assets [Line Items]
Amortization expense	$1,700,000	$1,800,000	$4,882,000	$5,052,000
Estimated Amortization Expense for Intangible Assets [Member]
Goodwill And Intangible Assets [Line Items]
Remainder 2013	1,600,000		1,600,000
Year 2014	6,400,000		6,400,000
Year 2015	6,400,000		6,400,000
Year 2016	6,400,000		6,400,000
Year 2017	6,400,000		6,400,000
Thereafter	$9,500,000		$9,500,000

Warranty_Costs_Additional_Info

Warranty Costs - Additional Information (Detail)	9 Months Ended
	Sep. 28, 2013
Maximum [Member]
Guarantor Obligations [Line Items]
Product warranty period	2 years
Extended product warranty period	36 months
Minimum [Member]
Guarantor Obligations [Line Items]
Product warranty period	3 months

Warranty_Costs_Changes_in_Carr

Warranty Costs - Changes in Carrying Amount of Accrued Product Warranty Costs (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012
Guarantees [Abstract]
Balance at beginning of period	$5,625	$4,898
Accrued current period warranty expense	1,758	1,651
Payments	-1,743	-1,435
Balance at end of period	$5,640	$5,114

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Income Tax Disclosure [Abstract]
Accrued interest and penalties	$0.40	$0.40

Pension_and_Other_Employee_Ben2

Pension and Other Employee Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$37	$25	$113	$75
Interest cost	246	273	738	819
Expected return on plan assets	-267	-268	-801	-804
Amortization of net gain	41	25	125	74
Net periodic benefit cost (income)	57	55	175	164
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	2	2
Interest cost	4	3	10	10
Expected return on plan assets
Amortization of prior service income			-1	-1
Amortization of net gain	-13	-13	-39	-39
Net periodic benefit cost (income)	($9)	($9)	($28)	($28)

Pension_and_Other_Employee_Ben3

Pension and Other Employee Benefits - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 28, 2013
Compensation And Retirement Disclosure [Abstract]
Defined benefit plan, supplementary contributions by employer	$3

Debt_Outstanding_Debt_Obligati

Debt - Outstanding Debt Obligations (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Total debt	$210,860	$266,901
Less: debt discount, net of accretion	-16,975	-19,306
Total debt, net of unaccreted discount	193,885	247,595
Less current portion of long-term debt	12,800	9,135
Total long-term debt, net of unaccreted discount	181,085	238,460
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total debt	25,000	79,304
Convertible Notes [Member]
Debt Instrument [Line Items]
Total debt	85,000	85,000
Term Notes [Member]
Debt Instrument [Line Items]
Total debt	96,250	100,000
Equipment and Working Capital Notes [Member]
Debt Instrument [Line Items]
Total debt	3,569	1,100
Mortgages [Member]
Debt Instrument [Line Items]
Total debt	715	963
Capital Leases [Member]
Debt Instrument [Line Items]
Total debt	73	99
Other [Member]
Debt Instrument [Line Items]
Total debt	$253	$435

Debt_Additional_Information_De

Debt - Additional Information (Detail)

9 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

Sep. 28, 2013

Dec. 31, 2012

Nov. 20, 2012

Sep. 28, 2013

Sep. 28, 2013

Dec. 31, 2012

Nov. 30, 2012

Nov. 30, 2012

Sep. 28, 2013

Dec. 31, 2012

Nov. 30, 2012

Nov. 30, 2012

Nov. 30, 2012

Nov. 30, 2012

Nov. 30, 2012

Sep. 28, 2013

Sep. 01, 2011

Mar. 07, 2011

Sep. 28, 2013

Nov. 30, 2009

Dec. 31, 2012

Dec. 31, 2011

Sep. 28, 2013

Dec. 31, 2012

Sep. 28, 2013

Sep. 28, 2013

Sep. 28, 2013

Sep. 28, 2013

Dec. 31, 2012

Dec. 31, 2012

Sep. 28, 2013

Sep. 28, 2013

Dec. 31, 2012

Dec. 31, 2012

USD ($)

USD ($)

Term Loan [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Maximum [Member]

Term Loan Facility [Member]

Revolving Credit Agreement [Member]

Revolving Credit Agreement [Member]

Revolving Credit Agreement [Member]

Eurodollar Loan [Member]

Eurodollar Loan [Member]

ABR Based Loans [Member]

ABR Based Loans [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Senior Secured Notes [Member]

Senior Secured Notes [Member]

Senior Secured Notes [Member]

Old Revolving Credit Agreement [Member]

Capital Leases [Member]

Capital Leases [Member]

Equipment and Working Capital Notes [Member]

Equipment and Working Capital Notes [Member]

Equipment and Working Capital Notes [Member]

Equipment and Working Capital Notes [Member]

Equipment and Working Capital Notes [Member]

Equipment and Working Capital Notes [Member]

Mortgages [Member]

Mortgages [Member]

Mortgages [Member]

Mortgages [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CNY

USD ($)

CNY

USD ($)

CNY

USD ($)

EUR (€)

USD ($)

EUR (€)

Debt Instrument [Line Items]

Availability under credit facility agreement

$100,000,000

$200,000,000

$65,000,000

Applicable margins for loans

1.38%

1.88%

0.38%

0.88%

Aggregate additional term loans

150,000,000

Credit facility maturity date

20-Nov-17

Debt instrument, maturity date

20-Nov-17

31-Mar-31

1-Dec-16

Outstanding on Revolving Credit Facility

25,000,000

79,300,000

Letters of credit outstanding

7,700,000

7,600,000

Amount available under credit facility

167,300,000

113,100,000

Percentage of capital stock not included in collateral

65.00%

Total debt

85,000,000

85,000,000

100,000

100,000

Coupon interest rate

2.75%

2.75%

Debt component in note payable

60,500,000

Equity component in note payable

24,500,000

Discount rate for debt component

8.25%

Debt issuance cost

3,700,000

Adjustments to additional paid-in capital of convertible debt

1,000,000

Debt issuance cost, Amortized

2,700,000

Effective interest rate of Senior Secured Notes

8.50%

8.75%

Face value of Senior Notes

210,000,000

Company issued Senior Secured Notes

8.13%

Deferred financing costs

6,700,000

Redemption of remaining senior secured notes

198,000,000

Loan

2,500,000

15,400,000

2,500,000

15,400,000

3,900,000

24,600,000

Remaining principal

2,500,000

15,400,000

2,500,000

15,400,000

1,100,000

7,000,000

Refinancing amount

1,100,000

6,500,000

Interest

5.54%

5.54%

5.04%

5.04%

2.90%

2.90%

Debt instrument due date

From July through September 2014

From July through September 2014

Debt instrument due date

1-Jun-16

1-Jun-16

Debt instrument due date

31-Aug-16

31-Aug-16

Mortgage Remaining Principal amount

700,000

500,000

1,000,000

700,000

Mortgage loan payable term

3 years

3 years

Borrowings under overdraft agreements

$0

$0

Debt_Carrying_Amount_of_Debt_D

Debt - Carrying Amount of Debt (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012	Sep. 28, 2013	Mar. 07, 2011
			Convertible Debt [Member]	Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount of debt			$85,000,000	$85,000,000
Unamortized discount			16,975,000
Carrying value of debt	$181,085,000	$238,460,000	$68,025,000

Debt_Interest_Expense_Associat

Debt - Interest Expense Associated with Convertible Notes (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013
Debt Disclosure [Abstract]
Contractual coupon rate of interest	$1,753
Accretion of Convertible Notes discount and amortization of deferred financing costs	2,594
Interest expense for the convertible notes	$4,347

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash dividend	$0.10	$0.05	$0.28	$0.10
Dividend paid	$2.70	$1.30	$2.70	$1.30
Dividend paid date			2-Oct-13	2-Oct-12
Dividends payable date of record				18-Sep-12
Compensation expense	0.6	0.7	2.4	2.2
Unrecognized compensation cost	3.6		3.6
Weighted average remaining period			3 years
Fair market value of the shares			$3.50
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares for vesting period			5 years

Stockholders_Equity_Companys_U

Stockholders' Equity - Company's Unvested Restricted Stock Grants (Detail) (USD $)	9 Months Ended
	Sep. 28, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Restricted shares unvested, beginning balance	162,586
Shares granted	127,326
Shares vested	-139,577
Restricted shares unvested, ending balance	150,335
Weighted-average grant date fair value, beginning balance	$18.67
Weighted-average grant date fair value, Shares granted	$24.53
Weighted-average grant date fair value, Shares vested	$21.50
Weighted-average grant date fair value, ending balance	$22.95

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 28, 2013	Sep. 28, 2013	Sep. 28, 2013	Jun. 29, 2013
			Interest Rate Swap [Member]	Interest Rate Swap [Member]
Debt Instrument [Line Items]
Outstanding borrowings			$98,125,000	$98,100,000
Fixed Rate			0.63%	0.63%
Ineffectiveness associated with the swap	$0	$0

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Summary of Swaps Recognized in Other Long-term Assets and in Other Comprehensive Income (Loss) (Detail) (Interest Rate Swap [Member], USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Jun. 29, 2013	Dec. 31, 2012
Interest Rate Swap [Member]
Derivative [Line Items]
Effective Date	30-Apr-13
Notional Amount	$98,125	$98,100
Fixed Rate, before applicable Margin	0.63%	0.63%
Maturity	30-Nov-16
Fair Value	$191

Concentrations_of_Credit_Segme2

Concentrations of Credit, Segment Data and Workforce - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Dec. 31, 2012
	Customer	Customer	Customer	Customer
			Segment
Segment Reporting [Abstract]
Percentage of customer segments	10.00%	10.00%	10.00%	10.00%
Number of customer represented greater than 10% of total sales	0	0	0	0
Sales contract payments due period			30 days
Number of operating segments			3
Number of reportable segments			1
Number of operating segments expected to have similar long-term average gross profit margins			3
Net assets of foreign subsidiaries	$128.50		$128.50		$117

Concentrations_of_Credit_Segme3

Concentrations of Credit, Segment Data and Workforce - Net Sales to Third Parties by Geographic Region (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Concentration Risk [Line Items]
Net sales	$175,443	$174,488	$541,688	$554,816
North America (Primarily U.S.) [Member]
Concentration Risk [Line Items]
Net sales	109,810	112,708	343,844	358,719
Europe [Member]
Concentration Risk [Line Items]
Net sales	52,315	49,832	160,895	162,356
Asia and Other [Member]
Concentration Risk [Line Items]
Net sales	$13,318	$11,948	$36,949	$33,741

Restructuring_Additional_Infor

Restructuring - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 28, 2013	Sep. 28, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$97,000	$655,000
2012 Altra Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	97,000	655,000
2012 Altra Plan [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring expenses		300,000
2012 Altra Plan [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring expenses		$600,000

Restructuring_Summary_of_Total

Restructuring - Summary of Total Restructuring Expense (Detail) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 28, 2013
Restructuring Cost and Reserve [Line Items]
Total cash expenses	$97	$655
2012 Altra Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance	137	653
Other	-40	2
Total cash expenses	$97	$655

Restructuring_Reconciliation_o

Restructuring - Reconciliation of Accrued Restructuring Costs (Detail) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 28, 2013
Related Party Transactions [Abstract]
Beginning Balance		$2,920
Restructuring expense incurred	97	655
Cash payments		-3,293
Ending Balance	$282	$282

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	Sep. 28, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]
Potential litigation	$0	$0

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Oct. 29, 2013	Oct. 31, 2013
					Subsequent Event [Member]	Subsequent Event [Member]
Subsequent Event [Line Items]
Defined benefit plan, supplementary contributions by employer			$3			$2
Dividend declared date					29-Oct-13
Dividend payable date					3-Jan-14
Dividend record date				18-Sep-12	18-Dec-13
Dividend per share	$0.10	$0.05	$0.28	$0.10	$0.10