XML 79 R56.htm IDEA: XBRL DOCUMENT
v3.20.1

Stockholders' Equity and Stock Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 29, 2020 | Mar. 31, 2019 | Mar. 29, 2020 | Mar. 31, 2019
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Stock-based compensation expense | $ 5,000 | $ 4,100 | $ 9,400 | $ 8,600
Performance-based restricted stock |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Percentage of shares that ultimately vest depending on growth in diluted earnings per share |  |  | 50.00% |
Percentage of shares that ultimately vest depending on the shareholder return relative to peer group of companies over vesting period |  |  | 50.00% |
Performance-based restricted stock | Non-employee directors and executive officers |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Granted (in shares) |  |  | 74,011 |
Granted, fair value (in dollars per share) |  |  | $ 99.85 |
Vesting period |  |  | 3 years |
Restricted stock units | Non-employee directors, executive officers and employees |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Granted (in shares) |  |  | 163,525 |
Granted, fair value (in dollars per share) |  |  | $ 84.01 |
Restricted stock units | Non-employee director |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Vesting period |  |  | 1 year |
Restricted stock units | Executive officers and employees |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Vesting period |  |  | 4 years |

X
- Definition Represents the percentage of performance-based shares that ultimately vests, depending upon the fiscal year growth in the diluted earnings per share. + References No definition available. + Details
Name: | ttek_ShareBasedCompensationArrangementPercentageOfAwardedSharesThatUltimatelyVests1
Namespace Prefix: | ttek_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of performance-based shares that ultimately vests, depending upon the fiscal year shareholder return relative to peer group of companies over the vesting period of the reporting entity. + References No definition available. + Details
Name: | ttek_ShareBasedCompensationArrangementPercentageOfAwardedSharesThatUltimatelyVests2
Namespace Prefix: | ttek_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=ttek_RestrictedStockPerformanceBasedAwardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=ttek_DirectorAndExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=ttek_DirectorExecutiveOfficerAndEmployeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_DirectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=ttek_ExecutiveOfficerAndEmployeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |