XML 59 R46.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Income Taxes (Details) $ in Millions | 3 Months Ended
--- | ---
Sep. 30, 2018 USD ($)
Income Tax Disclosure [Abstract] |
Federal tax expense decrease, deemed repatriation | $ 4.2
Federal tax expense increase, impact of rate change on deferred | $ 1.2

X
- Definition Amount of reasonable estimate for income tax expense (benefit) for remeasurement of deferred tax from change in tax rate pursuant to Tax Cuts and Jobs Act for which accounting for tax effect is incomplete. + References No definition available. + Details
Name: | alg_TaxCutsAndJobsActOf2017IncompleteAccountingChangeInTaxRateProvisionalIncomeTaxExpenseBenefit
Namespace Prefix: | alg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of reasonable estimate for income tax expense from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act for which accounting for tax effect is incomplete. + References No definition available. + Details
Name: | alg_TaxCutsAndJobsActOf2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalIncomeTaxExpense
Namespace Prefix: | alg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration