XML 55 R43.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Accounts Receivable - Net - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Dec. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2018
Accounts Receivable - Net and Revenue Recognition |  |  |
Period for billing and collecting unbilled receivables | 12 months |  |
Unbilled accounts receivable related to claims and requests for equitable adjustment on contracts | $ 74,000 |  | $ 74,000
Gains (losses) from claim settlement | 0 | $ 0 |
Billed accounts receivable related to U.S. federal government contracts | 80,300 |  | 81,500
US federal government unbilled contracts receivable | 265,974 |  | 267,739
U.S. federal government |  |  |
Accounts Receivable - Net and Revenue Recognition |  |  |
US federal government unbilled contracts receivable | $ 99,600 |  | $ 102,700

X
- Definition The amount of billed receivables that are derived from government contracts. + References No definition available. + Details
Name: | ttek_GovernmentContractReceivableBilledAmounts
Namespace Prefix: | ttek_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the unbilled accounts receivable related to claims and requests for equitable adjustment on contracts. + References No definition available. + Details
Name: | ttek_GovernmentContractReceivableUnbilledAmountsRelatedToClaimsAndRequestsForEquitableAdjustmentOnContract
Namespace Prefix: | ttek_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the period within which substantially all unbilled receivables are expected to be billed and collected. + References No definition available. + Details
Name: | ttek_UnbilledContractsReceivablePeriodForBillingAndCollection
Namespace Prefix: | ttek_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 + Details
Name: | us-gaap_GainLossRelatedToLitigationSettlement
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 912 -SubTopic 310 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=68054760&loc=d3e55302-109406 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3(c)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_UnbilledContractsReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_MajorCustomersAxis=ttek_FederalGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |