XML 103 R94.htm IDEA: XBRL DOCUMENT v3.19.1

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Mar. 31, 2019 USD ($) EquityFund
Contingencies And Commitments [Line Items]
Number of private equity funds | EquityFund	2
Commitments towards private equity funds	$ 7.7
Investment Commitments [Member]
Contingencies And Commitments [Line Items]
Aggregate investment committed in private equity funds	7.9
Private Equity Funds [Member]
Contingencies And Commitments [Line Items]
Contribution to private equity funds	$ 8.4

X

- Definition

Amount of contributions made that have been applied to private equity fund commitments.

+ References

No definition available.

+ Details

Name:	adtn_CommitmentsTowardsPrivateEquityFunds
Namespace Prefix:	adtn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Contingencies and commitments.

+ References

No definition available.

+ Details

Name:	adtn_ContingenciesAndCommitmentsLineItems
Namespace Prefix:	adtn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of investments in private equity funds.

+ References

No definition available.

+ Details

Name:	adtn_NumberOfPrivateEquityFunds
Namespace Prefix:	adtn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

+ Details

Name:	us-gaap_EquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Cost of the investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

+ Details

Name:	us-gaap_InvestmentOwnedAtCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_OtherCommitmentsAxis=adtn_InvestmentCommitmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: