Amendment fee.

No definition available.

Name:	aimc_AmendmentFee
Namespace Prefix:	aimc_
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Balance Type:	debit
Period Type:	duration

- Definition

Coupon interest rate.

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No definition available.

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Namespace Prefix:	aimc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of credit facility additional borrowing capacity.

+ References

No definition available.

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Namespace Prefix:	aimc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of notes.

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No definition available.

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Namespace Prefix:	aimc_
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Balance Type:	debit
Period Type:	duration

- Definition

Redemption of debt.

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No definition available.

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Balance Type:	debit
Period Type:	duration

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Surrender of notes for conversion end date.

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No definition available.

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Balance Type:	na
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- Definition

Carrying value as of the balance sheet date of payments made in excess of existing cash balances, which will be honored by the bank but reflected as a loan to the entity. Overdrafts generally have a very short time frame for correction or repayment and are therefore more similar to short-term bank financing than trade financing.

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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
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- Definition

This element represents the carrying value of a short-term real estate loan to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project, usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property. Note that there are separate concepts for the current and noncurrent portions of long-term construction loans.

+ References

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Period Type:	instant

- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Period Type:	duration

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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-Subparagraph (bbb)(2)
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Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

+ References

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Period Type:	duration

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Amount of the required periodic payments applied to interest.

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Period Type:	duration

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End date of debt instrument redemption period, in CCYY-MM-DD format.

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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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Period Type:	instant

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Period Type:	instant

- Definition

Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ References

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- Definition

Amount of mortgage loan in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, renewed or extended.

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-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SX 210.12-29(Footnote 6))
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Debt - Additional Information (Detail)							1 Months Ended		3 Months Ended			9 Months Ended		12 Months Ended
Debt - Additional Information (Detail)	Sep. 30, 2018 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 12, 2016 USD ($)	Oct. 21, 2016 USD ($)	Oct. 22, 2015 USD ($)	Sep. 01, 2011 USD ($)	Jan. 31, 2017 USD ($) shares	Mar. 31, 2011	Sep. 30, 2018 USD ($)	Sep. 30, 2018 EUR (€)	Mar. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)	Sep. 30, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2015 EUR (€)
Debt Instrument [Line Items]
Payment of remaining principal of revolving credit facility												$ 36,673,000	$ 39,036,000
Loss on extinguishment of convertible debt													$ 1,797,000
Carrying amount of financial instruments net of unamortized discount	$ 255,161,000								$ 255,161,000			255,161,000					$ 275,587,000
Borrowings under overdraft agreements	$ 0								$ 0			$ 0					0
Zlate Moravce, Slovakia [Member]
Debt Instrument [Line Items]
Interest rate	1.95%								1.95%			1.95%				1.95%
Description about maturity date of debt instrument												loan is due in installments from 2016 through 2020
Loan amount principal outstanding	$ 1,700,000								$ 1,700,000			$ 1,700,000				€ 1,500,000
Line of Credit [Member] \| Multicurrency [Member]
Debt Instrument [Line Items]
Maximum amount available				$ 250,000,000
Convertible Notes [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date								Mar. 01, 2031
Coupon interest rate						2.75%
Proceeds from the offering						$ 81,300,000
Percentage of convertible notes redeemable												100.00%
Surrender of notes for conversion end date												Jan. 09, 2017
Conversion of notes into shares (in shares)			0.390809
Principal amount of notes			$ 1,000
Conversion of notes into shares, amount		$ 39,300,000					$ 44,700,000
Conversion of notes into shares (in shares) \| shares		1,500,000					1,700,000
Loss on extinguishment of convertible debt		$ 1,900,000									$ 1,800,000
Carrying amount of financial instruments net of unamortized discount		$ 42,900,000
Redemption of debt							$ 900,000
Convertible Notes [Member] \| The Bank of New York Mellon Trust Company, N.A., [Member]
Debt Instrument [Line Items]
Notes redemption date												Jan. 12, 2017
Mortgages [Member] \| Heidelberg Germany [Member]
Debt Instrument [Line Items]
Interest rate	1.79%								1.79%			1.79%				1.79%
New mortgage amount	$ 1,000,000								$ 1,000,000			$ 1,000,000		$ 1,700,000		€ 900,000		€ 1,500,000
Description about maturity date of debt instrument												The mortgage has an interest rate of 1.79%, which is payable in monthly installments through August 2023.
Mortgages [Member] \| Esslingen Germany [Member]
Debt Instrument [Line Items]
Interest rate														2.50%				2.50%
Construction loan	$ 7,000,000								$ 7,000,000			$ 7,000,000		$ 6,700,000		€ 6,000,000		€ 6,000,000
Monthly installments														100,000	€ 100,000
Mortgages [Member] \| Angers France [Member]
Debt Instrument [Line Items]
Interest rate	1.85%								1.85%			1.85%				1.85%
Construction loan	$ 1,700,000								$ 1,700,000			$ 1,700,000		$ 2,300,000		€ 1,500,000		€ 2,100,000
Capital Leases [Member]
Debt Instrument [Line Items]
Principal amount of debt	100,000								100,000			100,000					200,000
2015 Credit Agreement [Member]
Debt Instrument [Line Items]
Amendment fee included in other non-current assets				600,000
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum amount available				425,000,000	$ 350,000,000
Debt instrument, maturity date					Oct. 22, 2020
Credit facility additional borrowing capacity				$ 75,000,000
Outstanding on revolving credit facility	$ 244,900,000								$ 244,900,000			$ 244,900,000
Interest rate	3.58%								3.58%			3.58%				3.58%
Amount available under credit facility	$ 175,900,000								$ 175,900,000			$ 175,900,000
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member] \| Eurodollar Loan [Member]
Debt Instrument [Line Items]
Applicable margins for loans	1.50%
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member] \| Minimum [Member] \| Eurodollar Loan [Member]
Debt Instrument [Line Items]
Applicable margins for loans					1.25%
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member] \| Minimum [Member] \| ABR Based Loans [Member]
Debt Instrument [Line Items]
Applicable margins for loans					0.25%
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member] \| Maximum [Member] \| Eurodollar Loan [Member]
Debt Instrument [Line Items]
Applicable margins for loans					2.00%
2015 Credit Agreement [Member] \| Line of Credit [Member] \| 2015 Revolving Credit Facility [Member] \| Maximum [Member] \| ABR Based Loans [Member]
Debt Instrument [Line Items]
Applicable margins for loans					1.00%
2015 Credit Agreement [Member] \| Line of Credit [Member] \| Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding	$ 4,200,000								4,200,000			$ 4,200,000					$ 3,500,000
2015 Credit Agreement [Member] \| Foreign Line of Credit [Member] \| 2015 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Payment of remaining principal of revolving credit facility									$ 12,200,000	€ 10,500,000