Tetra Tech (TTEK) 10-Q 4 Feb 22 2022 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Jan. 02, 2022	Jan. 24, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jan. 2, 2022
Document Transition Report	false
Entity File Number	0-19655
Entity Registrant Name	TETRA TECH, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-4148514
Entity Address, Address Line One	3475 East Foothill Boulevard
Entity Address, City or Town	Pasadena
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91107
City Area Code	626
Local Phone Number	351-4664
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	TTEK
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		53,999,410
Entity Central Index Key	0000831641
Amendment Flag	false
Current Fiscal Year End Date	--10-02
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Current assets:
Cash and cash equivalents	$ 205,542	$ 166,568
Accounts receivable, net	696,586	668,998
Contract assets	98,439	103,784
Prepaid expenses and other current assets	103,266	112,338
Income taxes receivable	9,567	14,260
Total current assets	1,113,400	1,065,948
Property and equipment, net	35,428	37,733
Right-of-use assets, operating leases	212,018	215,422
Investments in unconsolidated joint ventures	3,893	3,282
Goodwill	1,123,060	1,108,578
Intangible assets, net	36,535	37,990
Deferred tax assets	58,876	54,413
Other long-term assets	57,246	53,196
Total assets	2,640,456	2,576,562
Current liabilities:
Accounts payable	142,847	128,767
Accrued compensation	166,002	206,322
Contract liabilities	219,519	190,403
Short-term lease liabilities, operating leases	65,185	67,452
Current portion of long-term debt and other short-term borrowings	16,728	12,504
Current contingent earn-out liabilities	21,931	19,520
Other current liabilities	217,056	223,515
Total current liabilities	849,268	848,483
Deferred tax liabilities	13,916	10,563
Long-term debt	246,875	200,000
Long-term lease liabilities, operating leases	172,795	174,285
Long-term contingent earn-out liabilities	43,839	39,777
Other long-term liabilities	75,818	69,163
Commitments and contingencies (Note 16)
Equity:
Preferred stock - authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at January 2, 2022 and October 3, 2021	0	0
Common stock - authorized, 150,000 shares of $0.01 par value; issued and outstanding, 53,999 and 53,981 shares at January 2, 2022 and October 3, 2021, respectively	540	540
Accumulated other comprehensive loss	(123,048)	(125,028)
Retained earnings	1,360,390	1,358,726
Tetra Tech stockholders’ equity	1,237,882	1,234,238
Noncontrolling interests	63	53
Total stockholders' equity	1,237,945	1,234,291
Total liabilities and stockholders' equity	$ 2,640,456	$ 2,576,562

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jan. 02, 2022	Oct. 03, 2021
Statement of Financial Position [Abstract]
Preferred stock, authorized shares (in shares)	2,000,000	2,000,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, authorized shares (in shares)	150,000,000	150,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares issued (in shares)	53,999,000	53,981,000
Common stock, shares outstanding (in shares)	53,999,000	53,981,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Revenue	$ 858,510	$ 765,104
Gross profit	139,766	116,310
Selling, general and administrative expenses	(52,546)	(50,058)
Income from operations	87,220	66,252
Interest expense, net	(2,904)	(3,026)
Income before income tax expense	84,316	63,226
Income tax expense	(15,817)	(10,778)
Net income	68,499	52,448
Net income attributable to noncontrolling interests	(10)	(12)
Net income attributable to Tetra Tech	$ 68,489	$ 52,436
Earnings per share attributable to Tetra Tech:
Basic (in dollars per share)	$ 1.27	$ 0.97
Diluted (in dollars per share)	$ 1.25	$ 0.96
Weighted-average common shares outstanding:
Basic (in shares)	53,937	53,927
Diluted (in shares)	54,577	54,637
Subcontractor costs
Cost of revenue	$ (179,177)	$ (159,933)
Other costs of revenue
Cost of revenue	$ (539,567)	$ (488,861)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 68,499	$ 52,448
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	(686)	32,393
Gain on cash flow hedge valuations, net of tax	2,666	1,476
Other comprehensive income, net of tax	1,980	33,869
Comprehensive income, net of tax	70,479	86,317
Comprehensive income attributable to noncontrolling interests, net of tax	10	14
Comprehensive income attributable to Tetra Tech, net of tax	$ 70,469	$ 86,303

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Cash flows from operating activities:
Net income	$ 68,499	$ 52,448
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,111	6,238
Equity in income of unconsolidated joint ventures	(1,440)	(1,107)
Distributions of earnings from unconsolidated joint ventures	842	931
Amortization of stock-based awards	5,828	4,898
Deferred income taxes	(878)	954
(Gain) loss on sale of property and equipment	239	(7)
Changes in operating assets and liabilities, net of effects of business acquisitions:
Accounts receivable and contract assets	(21,560)	(11,400)
Prepaid expenses and other assets	5,364	11,813
Accounts payable	14,056	23,631
Accrued compensation	(40,321)	(61,690)
Contract liabilities	29,227	27,392
Other liabilities	11,615	(23,373)
Income taxes receivable/payable	4,837	2,452
Net cash provided by operating activities	82,419	33,180
Cash flows from investing activities:
Payments for business acquisitions, net of cash acquired	(8,858)	0
Capital expenditures	(1,518)	(1,795)
Proceeds from sales of assets	3,514	9
Net cash used in investing activities	(6,862)	(1,786)
Cash flows from financing activities:
Proceeds from borrowings	50,831	123,533
Repayments on long-term debt	(3,956)	(114,752)
Bank overdrafts	4,158	0
Repurchases of common stock	(50,000)	(15,000)
Taxes paid on vested restricted stock	(24,949)	(17,330)
Stock options exercised	960	7,495
Dividends paid	(10,793)	(9,198)
Payments of contingent earn-out liabilities	(1,720)	(7,037)
Principal payments on finance leases	(945)	(538)
Net cash used in financing activities	(36,414)	(32,827)
Effect of exchange rate changes on cash and cash equivalents	(169)	7,356
Net increase in cash and cash equivalents	38,974	5,923
Cash and cash equivalents at beginning of period	166,568	157,515
Cash and cash equivalents at end of period	205,542	163,438
Cash paid during the period for:
Interest	2,456	1,968
Income taxes, net of refunds received of $2.3 million and $1.1 million	$ 11,535	$ 5,696

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Statement of Cash Flows [Abstract]
Income tax refunds	$ 2.3	$ 1.1

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Total Tetra Tech Equity	Non-Controlling Interests
Beginning balance (in shares) at Sep. 27, 2020		53,797
Beginning balance at Sep. 27, 2020	$ 1,037,373	$ 538	$ 0	$ (161,786)	$ 1,198,567	$ 1,037,319	$ 54
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52,448				52,436	52,436	12
Other comprehensive income (loss)	33,869			33,867		33,867	2
Cash dividends per common share	(9,198)				(9,198)	(9,198)
Stock-based compensation	4,898		4,898			4,898
Restricted & performance shares released (in shares)		209
Restricted & performance shares released	(17,330)	$ 2	(17,332)			(17,330)
Stock options exercised (in shares)		198
Stock options exercised	7,495	$ 2	7,493			7,495
Shares issued for Employee Stock Purchase Plan (in shares)		124
Shares issued for Employee Stock Purchase Plan	10,699	$ 1	10,698			10,699
Stock repurchases (in shares)		(135)
Stock repurchases	(15,000)	$ (1)	(5,757)		(9,242)	(15,000)
Ending balance (in shares) at Dec. 27, 2020		54,193
Ending balance at Dec. 27, 2020	1,105,254	$ 542	0	(127,919)	1,232,563	1,105,186	68
Beginning balance (in shares) at Oct. 03, 2021		53,981
Beginning balance at Oct. 03, 2021	1,234,291	$ 540	0	(125,028)	1,358,726	1,234,238	53
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	68,499				68,489	68,489	10
Other comprehensive income (loss)	1,980			1,980		1,980
Cash dividends per common share	(10,793)				(10,793)	(10,793)
Stock-based compensation	5,828		5,828			5,828
Restricted & performance shares released (in shares)		182
Restricted & performance shares released	(24,949)	$ 2	(18,916)		(6,035)	(24,949)
Stock options exercised (in shares)		20
Stock options exercised	960		960			960
Shares issued for Employee Stock Purchase Plan (in shares)		106
Shares issued for Employee Stock Purchase Plan	12,129	$ 1	12,128			12,129
Stock repurchases (in shares)		(290)
Stock repurchases	(50,000)	$ (3)			(49,997)	(50,000)
Ending balance (in shares) at Jan. 02, 2022		53,999
Ending balance at Jan. 02, 2022	$ 1,237,945	$ 540	$ 0	$ (123,048)	$ 1,360,390	$ 1,237,882	$ 63

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	Dec. 20, 2021	Dec. 11, 2020	Jan. 02, 2022	Dec. 27, 2020
Statement of Stockholders' Equity [Abstract]
Dividend paid per share (in dollars per share)	$ 0.20	$ 0.17	$ 0.20	$ 0.17

Basis of Presentation

Basis of Presentation	3 Months Ended
	Jan. 02, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements and related notes of Tetra Tech, Inc. (“we,” “us,” “our” or "Tetra Tech") have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all of the information and footnotes required by U.S. GAAP for complete financial statements and, therefore, should be read in conjunction with the audited consolidated financial statements and the notes contained in our Annual Report on Form 10-K for the fiscal year ended October 3, 2021. These financial statements reflect all normal recurring adjustments that are considered necessary for a fair statement of our financial position, results of operations and cash flows for the interim periods presented. The results of operations and cash flows for any interim period are not necessarily indicative of results for the full year or for future years . Beginning in fiscal 2022, we aligned our operations to better serve our clients and markets, and created a new High Performance Buildings ("HPB") division in our Commercial/International Services Group ("CIG") reportable segment. As a result, we transferred some related operations in our Government Services Group (" GSG") reportable segment to our CIG reportable segment. Prior year amounts for reportable segments have been reclassified to conform to the current year presentation.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Jan. 02, 2022
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2019-12, which simplifies the accounting for income taxes by removing certain exceptions to general principles in Topic 740 and amending certain existing guidance for clarity . We adopted this guidance in the first quarter of fiscal 2022, and the adoption did not have an impact on our consolidated financial statements. In May 2020, the Securities and Exchange Commission issued guidance amending certain financial disclosures about acquired and disposed businesses. The amendments are designed to assist registrants in making more meaningful determinations of whether a subsidiary or an acquired or disposed business is significant, and to improve the related disclosure requirements. We adopted this guidance in the first quarter of fiscal 2022, and the adoption did not have an impact on our consolidated financial statements. In October 2021, the FASB issued ASU 2021-08, which requires the recognition and measurement of contract assets and contract liabilities acquired in a business combination in accordance with Accounting Standards Codification Topic 606, "Revenue from Contracts with Customers" ("ASC 606"). Considerations to determine the amount of contract assets and contract liabilities to record at the acquisition date include the terms of the acquired contract, such as timing of payment, identification of each performance obligation in the contract and allocation of the contract transaction price to each identified performance obligation on a relative standalone selling price basis as of contract inception. ASU 2021-08 is effective for us beginning in the first quarter of fiscal 2023. ASU 2021-08 should be applied prospectively for acquisitions occurring on or after the effective date of the amendments. Early adoption of the proposed amendments would be permitted, including adoption in an interim period. We are currently assessing the impact this standard will have on our consolidated financial statements. In November 2021, the FASB issued ASU 2021-10, Government Assistance (Topic 832), which requires disclosures for transactions with a government authority that are accounted for by applying a grant or contribution model by analogy, including (1) the types of transactions, (2) the accounting for those transactions, and (3) the effect of those transactions on an entity's financial statements. ASU 2021-10 is effective for us beginning in the first quarter of fiscal 2023, with early adoption permitted. This guidance should be applied prospectively to all transactions that are reflected in the financial statements at the date of initial application and to new transactions that are entered into after that date, or retrospectively. We do not expect the adoption of this guidance to have an impact on our consolidated financial statements.

Revenue and Contract Balances

Revenue and Contract Balances	3 Months Ended
	Jan. 02, 2022
Revenue from Contract with Customer [Abstract]
Revenue and Contract Balances	Revenue and Contract Balances Disaggregation of Revenue We disaggregate revenue by client sector and contract type, as we believe it best depicts how the nature, timing, and uncertainty of revenue and cash flows are affected by economic factors. The following tables present revenue disaggregated by client sector and contract type: Three Months Ended January 2, December 27, (in thousands) Client Sector: U.S. state and local government $ 159,008 $ 125,008 U.S. federal government (1) 266,797 265,873 U.S. commercial 176,904 157,787 International (2) 255,801 216,436 Total $ 858,510 $ 765,104 Contract Type: Fixed-price $ 331,248 $ 274,406 Time-and-materials 395,648 355,270 Cost-plus 131,614 135,428 Total $ 858,510 $ 765,104 (1) Includes revenue generated under U.S. federal government contracts performed outside the United States. (2) Includes revenue generated from foreign operations, primarily in Canada, Australia, the United Kingdom, and revenue generated from non-U.S. clients. Other than the U.S. federal government, no single client accounted for more than 10% of our revenue for the three months ended January 2, 2022 and December 27, 2020. Contract Assets and Contract Liabilities We invoice customers based on the contractual terms of each contract. However, the timing of revenue recognition may differ from the timing of invoice issuance. Contract assets represent revenue recognized in excess of the amounts for which we have the contractual right to bill our customers. Such amounts are recoverable from customers based upon various measures of performance, including achievement of certain milestones or completion of a contract. In addition, many of our time and materials arrangements are billed in arrears pursuant to contract terms that are standard within the industry, resulting in contract assets and/or unbilled receivables being recorded, as revenue is recognized in advance of billings. Contract retentions, included in contract assets, represent amounts withheld by clients until certain conditions are met or the project is completed, which may extend beyond one year. Contract liabilities consist of billings in excess of revenue recognized. Contract liabilities decrease as we recognize revenue from the satisfaction of the related performance obligation and increase as billings in advance of revenue recognition occur. Contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. There were no substantial non-current contract assets or liabilities for the periods presented. Net contract assets/liabilities consisted of the following: Balance at January 2, October 3, 2021 (in thousands) Contract assets (1) $ 98,439 $ 103,784 Contract liabilities (219,519) (190,403) Net contract liabilities $ (121,080) $ (86,619) (1) Inclu des $13.5 million and $12.2 million of contract retentions as of January 2, 2022 and October 3, 2021, respectively. In the first quarters of fiscal 2022 and 2021, we recognized revenue of approximately $63 million and $60 million, respectively, from amounts included in the contract liability balances at the end of fiscal 2021 and 2020, respectively. We recognize revenue primarily using the cost-to-cost measure of progress to estimate progress towards completion. Changes in those estimates could result in the recognition of cumulative catch-up adjustments to the contract’s inception-to-date revenue, costs and profit in the period in which such changes are made. As a result, we recognized net favorable revenue and operating income adjustments of $2.8 million in the first quarter of fiscal 2022. For the first quarter of fiscal 2021, these net adjustments to our revenue and operating income were immaterial. C hanges in revenue and cost estimates could also result in a projected loss, determined at the contract level, which would be recorded immediately in earnings. As of January 2, 2022 and October 3, 2021, our consolidated balance sheets included liabilities for anticipated losses of $14.2 million and $12.7 million, respectively. The estimated cost to complete these related contracts as of January 2, 2022 and October 3, 2021 was approximately $116 million and $104 million, respectively. Accounts Receivable, Net Net accounts receivable consisted of the following: Balance at January 2, October 3, (in thousands) Billed $ 441,652 $ 432,814 Unbilled 259,918 240,536 Total accounts receivable 701,570 673,350 Allowance for doubtful accounts (4,984) (4,352) Total accounts receivable, net $ 696,586 $ 668,998 Billed accounts receivable represent amounts billed to clients that have not been collected. Unbilled accounts receivable, which represent an unconditional right to payment subject only to the passage of time, include unbilled amounts typically resulting from revenue recognized but not yet billed pursuant to contract terms or billed after the period end date. Substantially all of our unbilled receivables at January 2, 2022 are expected to be billed and collecte d within 12 months. The allowance for doubtful accounts represents amounts that are expected to become uncollectible or unrealizable in the future. We determine an estimated allowance for uncollectible accounts based on management's consideration of trends in the actual and forecasted credit quality of our clients, including delinquency and payment history; type of client, such as a government agency or a commercial sector client; and general economic and industry conditions, including the potential impacts of the coronavirus disease 2019 ("COVID-19") pandemic, that may affect our clients' ability to pay. Total accounts receivable at January 2, 2022 and October 3, 2021 included approximately $11 million for each period, related to claims, including requests for equitable adjustment, on contracts that provide for price redetermination. Claims are amounts in excess of agreed contract prices that we seek to collect from our clients or other third parties for delays, errors in specifications and designs, contract terminations, change orders in dispute or unapproved as to both scope and price, or other causes of unanticipated additional costs. Factors considered in determining whether revenue associated with claims (including change orders in dispute and unapproved change orders in regards to both scope and price) should be recognized include the following: (a) the contract or other evidence provides a legal basis for the claim, (b) additional costs were caused by circumstances that were unforeseen at the contract date and not the result of deficiencies in our performance, (c) claim-related costs are identifiable and considered reasonable in view of the work performed, and (d) evidence supporting the claim is objective and verifiable. This can lead to a situation in which costs are recognized in one period and revenue is recognized in a subsequent period when a client agreement is obtained, or a claims resolution occurs. We regularly evaluate all unsettled claim amounts and record appropriate adjustme nts to revenue when it is probable that the claim will result in a different contract value than the amount previously estimated. In the first quarters of fiscal 2022 and fiscal 2021, we recorded no gains or losses related to claims. Other than the U.S. federal government, no single client accounted for more than 10% of our accounts receivable at January 2, 2022 and October 3, 2021. Remaining Unsatisfied Performance Obligations (“RUPO”) Our RUPO represents a measure of the total dollar value of work to be performed on contracts awarded and in progress. We h ad $3.4 billion of RUPO as of January 2, 2022. RUPO increases with awards from new contracts or additions on existing contracts and decreases as work is performed and revenue is recognized on existing contracts. RUPO may also decrease when projects are canceled or modified in scope. We include a contract within our RUPO when the contract is awarded and an agreement on contract terms has been reached. We expect to satisfy our RUPO as of January 2, 2022 over the following periods: Amount (in thousands) Within 12 months $ 2,042,908 Beyond 1,392,475 Total $ 3,435,383 Although RUPO reflects business that is considered to be firm, cancellations, deferrals or scope adjustments may occur. RUPO is adjusted to reflect any known project cancellations, revisions to project scope and cost, foreign currency exchange fluctuations and project deferrals, as appropriate. Our operations and maintenance contracts can generally be terminated by the clients without a substantive financial penalty. Therefore, the remaining performance obligations on such contracts are limited to the notice period required for the termination (usually 30, 60, or 90 days).

Acquisitions

Acquisitions	3 Months Ended
	Jan. 02, 2022
Business Combination and Asset Acquisition [Abstract]
Acquisitions	Acquisitions In the first quarter of fiscal 2022, our acquisition activity was immaterial. In fiscal 2021, we acquired Coanda Research and Development Corporation ("CRD"), The Kaizen Company (“KZN”), IBRA-RMAC Automation Solutions (“IRM”), and the partnership interests of Hoare Lea, LLP and Subsidiaries ("HLE"). CRD is based in Burnaby, British Columbia and provides world-class expertise in computational fluid dynamics and utilizes industry-leading capabilities to solve complex engineering science problems for commercial customers, across a broad range of industries. KZN is based in Washington, DC and provides international development advisory and management consulting services offering a suite of innovative tools that support advanced solutions in health, education, governance, peace and stability, and sustainable economic growth. IRM is based in San Diego, California, and provides digital water transformation consulting services and an innovative suite of tools to address complex water system modernization challenges. HLE is a leader in sustainable engineering design based in Bristol, United Kingdom. It was established in 1862 and is an award-winning high-end consultancy firm in the United Kingdom, with more than 900 employees, providing innovative solutions to complex engineering and design challenges for sustainable infrastructure and high performance buildings. CRD and HLE are part of our CIG segment, and KZN and IRM are part of our GSG segment. The total fair value of the purchase price for these acquisitions was $151.7 million. This amount was comprised of $101.4 million in initial cash payments made to the sellers, and $50.3 million for the estimated fair value of contingent earn-out obligations, with a maximum of $74.0 million, based upon the achievement of specified operating income targets in each of the three Goodwill additions resulting from the above business combinations are primarily attributable to the existing workforce of the acquired companies and the synergies expected to arise after the acquisitions. The fiscal 2021 goodwill additions represent the significant technical expertise residing in embedded workforces that are sought out by clients and the long-standing reputation of HLE. In addition, these acquired capabilities, when combined with our exis ting global consulting and engineering business, result in opportunities that allow us to provide services under contracts that could not have been pursued individually by either us or the acquired compan ies. T he results of these acquisitions were included in our consolidated financial statements from their respective closing dates. These acquisitions were not considered material, individually or in the aggregate, to our consolidated financial statements. As a result, no pro forma information has been provided. Backlog, client relations and trade name intangible assets include the fair value of existing contracts and the underlying customer relationships with lives ranging from one three Most of our acquisition agreements include contingent earn-out agreements, which are generally based on the achievement of future operating income thresholds. The contingent earn-out arrangements are based on our valuations of the acquired companies and reduce the risk of overpaying for acquisitions if the projected financial results are not achieved. The fair values of any earn-out arrangements are included as part of the purchase price of the acquired companies on their respective acquisition dates. For each transaction, we estimate the fair value of contingent earn-out payments as part of the initial purchase price and record the estimated fair value of contingent consideration as a liability in “Current contingent earn-out liabilities” and “Long-term contingent earn-out liabilities” on the consolidated balance sheets. We consider several factors when determining that contingent earn-out liabilities are part of the purchase price, including the following: (1) the valuation of our acquisitions is not supported solely by the initial consideration paid, and the contingent earn-out formula is a critical and material component of the valuation approach to determining the purchase price; and (2) the former owners of acquired companies that remain as key employees receive compensation other than contingent earn-out payments at a reasonable level compared with the compensation of our other key employees. The contingent earn-out payments are not affected by employment termination. We measure our contingent earn-out liabilities at fair value on a recurring basis using significant unobservable inputs classified within Level 3 of the fair value hierarchy. We use a probability-weighted discounted income approach as a valuation technique to convert future estimated cash flows to a single present value amount. The significant unobservable inputs used in the fair value measurements are operating income projections over the earn-out period (generally three We review and re-assess the estimated fair value of contingent consideration on a quarterly basis, and the updated fair value could differ materially from the initial estimates. Changes in the estimated fair value of our contingent earn-out liabilities related to the time component of the present value calculation are reported in interest expense. Adjustments to the estimated fair value related to changes in all other unobservable inputs are reported in operating income. In the first quarter of fiscal 2022, we evaluated our estimates for contingent consideration liabilities for the remaining earn-out periods for each individual acquisition, which included a review of their financial results to-date, the status of ongoing projects in their RUPO, and the inventory of prospective new contract awards. In addition, we considered the potential impact of the global economic disruption due to the COVID-19 pandemic on our operating income projections over the various earn-out peri ods. For the first quarters of fiscal 2022 and 2021, we had no material adjustments to our contingent earn-out liabilities in operating income. At January 2, 2022, there was a total potential ma ximum of $119.4 million of outstanding contingent consideration related to acquisitions. Of this amount, $65.8 million was estimated as the fair value and accrued on our consolidated balance sheet. If the global economic disruption related to the COVID-19 pandemic is prolo nged, we could have significant reductions in our contingent earn-out liabilities and related gains in our operating income in future periods.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Jan. 02, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The following table summarizes the changes in the carrying value of goodwill by reportable segment: GSG CIG Total (in thousands) Balance at October 3, 2021 $ 538,433 $ 570,145 $ 1,108,578 Goodwill reallocation (51,497) 51,497 — Acquisition activity 14,671 — 14,671 Translation and adjustments 44 (233) (189) Balance at January 2, 2022 $ 501,651 $ 621,409 $ 1,123,060 Our goodwill balances reflect the goodwill reallocation related to the creation of our new HPB division on the first day of fiscal 2022, which included a transfer of some related operations in our GSG reportable segment to our CIG reportable segment. The foreign currency translation adjustments resulted from our foreign subsidiaries with functional currencies that are different than our reporting currency. These amounts are presented net of reductions from historical impairment adjustments. The gross amounts o f goodwill for GSG were $519.4 million and $556.1 million at January 2, 2022 and October 3, 2021, respectively, excluding accumulated impairment of $17.7 million for each period. The gross amounts of goodwill for CIG were $742.9 million and $691.6 million at January 2, 2022 and October 3, 2021, respectively, excluding accumulated impairment of $121.5 million for each period. We perform our annual goodwill impairment review at the beginning of our fiscal fourth quarter. Our most recent annual review at June 28, 2021 (i.e. the first day of our fourth quarter in fiscal 2021) indicated that we had no impairment of goodwill, and all of our reporting units had estimated fair values that were in excess of their carrying values, including goodwill. As of June 28, 2021, and after the reallocation of goodwill on the first day of fiscal 2022, we had no reporting units that had estimated fair values that exceeded their carrying values by less than 150%. We also regularly evaluate whether events and circumstances have occurred that may indicate a potential change in the recoverability of goodwill. We perform interim goodwill impairment reviews between our annual reviews if certain events and circumstances have occurred, such as a deterioration in general economic conditions; an increase in the competitive environment; a change in management, key personnel, strategy or customers; negative or declining cash flows; or a decline in actual or planned revenue or earnings compared with actual and projected results of relevant prior periods. Although we believe that our estimates of fair value for these reporting units are reasonable, if financial performance for these reporting units falls significantly below our expectations or market prices for similar business decline, the goodwill for these reporting units could become impaired. The following table presents the gross amount and accumulated amortization of our acquired identifiable intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets: Period Ended January 2, 2022 October 3, 2021 Weighted- Gross Accumulated Net Amount Gross Accumulated Net Amount ($ in thousands) Client relations 6.4 $ 43,646 $ (18,723) $ 24,923 $ 69,455 $ (43,984) $ 25,471 Backlog 1.2 32,113 (28,573) 3,540 34,577 (30,670) 3,907 Technology and trade names 4.3 14,936 (6,864) 8,072 14,939 (6,327) 8,612 Total $ 90,695 $ (54,160) $ 36,535 $ 118,971 $ (80,981) $ 37,990 Amortization expense for the three months ended January 2, 2022 wa s $2.7 million, compared to $3.4 million for the prior-year periods. Estimated amortization expense for the remainder of fiscal 2022 and succeeding years is as follows: Amount (in thousands) 2022 $ 7,733 2023 7,859 2024 5,193 2025 4,359 2026 3,963 Beyond 7,428 Total $ 36,535

Property and Equipment

Property and Equipment	3 Months Ended
	Jan. 02, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consisted of the following: Balance at January 2, October 3, (in thousands) Equipment, furniture and fixtures $ 95,228 $ 94,780 Leasehold improvements 36,472 36,462 Total property and equipment 131,700 131,242 Accumulated depreciation (96,272) (93,509) Property and equipment, net $ 35,428 $ 37,733 The depreciation expense related to property and equipment wa s $3.4 million for the three months ended January 2, 2022, compared to $2.9 million

Stock Repurchase and Dividends

Stock Repurchase and Dividends	3 Months Ended
	Jan. 02, 2022
Stock Repurchase And Dividends [Abstract]
Stock Repurchase and Dividends	Stock Repurchase and Dividends On October 5, 2021, the Board of Directors authorized a new stock repurchase program under which we could repurchase up to $400 million of our common stock in addition to the $147.8 million remaining under the previous stock repurchase program at October 3, 2021 . In the first quarter of fiscal 2022, we repurchased and settled 290,196 shares with an average price of $172.30 per share for a total cost of $50.0 million in the open market. At January 2, 2022, we had a remaining balance of $497.8 million under our stock repurchase program. The following table presents dividends declared and paid in the first quarters of fiscal 2022 and 2021: Declare Date Dividend Paid Per Share Record Date Payment Date Dividend Paid November 15, 2021 $ 0.20 December 2, 2021 December 20, 2021 $ 10,793 November 9, 2020 $ 0.17 November 30, 2020 December 11, 2020 $ 9,198 Subsequent Event. On January 31, 2022, the Board of Directors declared a quarterly cash dividend of $0.20 pe r share payable on February 25, 2022 to stockholders of record as of the close of business on February 11, 2022.

Leases

Leases	3 Months Ended
	Jan. 02, 2022
Leases [Abstract]
Leases	Leases Our operating leases are primarily for corporate and project office spaces. To a much lesser extent, we have operating leases for vehicles and equipment. Our operating leases have remaining lease terms of one month to twelve years, some of which may include options to extend the leases for up to five years. We determine if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets and current and long-term operating lease liabilities in the consolidated balance sheets. Our finance leases are primarily for certain information technology equipment. The related ROU assets and lease liabilities were immaterial, and are included in "Property and equipment, net", "Other current liabilities" and "Other long-term liabilities", accordingly, in the consolidated balance sheets at January 2, 2022 and October 3, 2021. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, incremental borrowing rates are used based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset at the commencement date also includes any lease payments made to the lessor at or before the commencement date and initial direct costs less lease incentives received. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. The components of lease costs are as follows: Three Months Ended January 2, December 27, (in thousands) Operating lease cost $ 21,751 $ 22,069 Sublease income (125) (29) Total lease cost $ 21,626 $ 22,040 Supplemental cash flow information related to leases is as follows: Three Months Ended January 2, December 27, (in thousands) Operating cash flows for operating leases $ 17,519 $ 18,800 Right-of-use assets obtained in exchange for new operating lease liabilities $ 12,347 $ 10,293 Supplemental balance sheet and other information related to leases are as follows: Balance at January 2, 2022 October 3, 2021 (in thousands) Operating leases: Right-of-use assets $ 212,018 $ 215,422 Lease liabilities: Current 65,185 67,452 Long-term 172,795 174,285 Total operating lease liabilities $ 237,980 $ 241,737 Weighted-average remaining lease term: Operating leases 5 years 5 years Weighted-average discount rate: Operating leases 2.1 % 2.2 % As of January 2, 2022, we do not have any material additional operating leases that have not yet commenced. A maturity analysis of the future undiscounted cash flows associated with our operating lease liabilities at January 2, 2022 is as follows: Amount (in thousands) 2022 $ 53,596 2023 57,830 2024 42,775 2025 31,876 2026 21,407 Beyond 45,581 Total lease payments 253,065 Less: imputed interest (15,085) Total present value of lease liabilities $ 237,980
Leases	Leases Our operating leases are primarily for corporate and project office spaces. To a much lesser extent, we have operating leases for vehicles and equipment. Our operating leases have remaining lease terms of one month to twelve years, some of which may include options to extend the leases for up to five years. We determine if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets and current and long-term operating lease liabilities in the consolidated balance sheets. Our finance leases are primarily for certain information technology equipment. The related ROU assets and lease liabilities were immaterial, and are included in "Property and equipment, net", "Other current liabilities" and "Other long-term liabilities", accordingly, in the consolidated balance sheets at January 2, 2022 and October 3, 2021. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, incremental borrowing rates are used based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset at the commencement date also includes any lease payments made to the lessor at or before the commencement date and initial direct costs less lease incentives received. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. The components of lease costs are as follows: Three Months Ended January 2, December 27, (in thousands) Operating lease cost $ 21,751 $ 22,069 Sublease income (125) (29) Total lease cost $ 21,626 $ 22,040 Supplemental cash flow information related to leases is as follows: Three Months Ended January 2, December 27, (in thousands) Operating cash flows for operating leases $ 17,519 $ 18,800 Right-of-use assets obtained in exchange for new operating lease liabilities $ 12,347 $ 10,293 Supplemental balance sheet and other information related to leases are as follows: Balance at January 2, 2022 October 3, 2021 (in thousands) Operating leases: Right-of-use assets $ 212,018 $ 215,422 Lease liabilities: Current 65,185 67,452 Long-term 172,795 174,285 Total operating lease liabilities $ 237,980 $ 241,737 Weighted-average remaining lease term: Operating leases 5 years 5 years Weighted-average discount rate: Operating leases 2.1 % 2.2 % As of January 2, 2022, we do not have any material additional operating leases that have not yet commenced. A maturity analysis of the future undiscounted cash flows associated with our operating lease liabilities at January 2, 2022 is as follows: Amount (in thousands) 2022 $ 53,596 2023 57,830 2024 42,775 2025 31,876 2026 21,407 Beyond 45,581 Total lease payments 253,065 Less: imputed interest (15,085) Total present value of lease liabilities $ 237,980

Stockholders' Equity and Stock

Stockholders' Equity and Stock Compensation Plans	3 Months Ended
	Jan. 02, 2022
Stockholders' Equity Note [Abstract]
Stockholders' Equity and Stock Compensation Plans	Stockholders’ Equity and Stock Compensation Plans We recogniz e the fair value of our stock-based awards as compensation expense on a straight-line basis over the requisite service period in which the award vests. Stock-based compensation expense for the three months ended January 2, 2022 was $5.8 million , compared to $4.9 million for the same period last year. Most of these amounts were included in selling, general and administrative expenses on our consolidated statements of income. In the first quarter of fiscal 2022, we awarded 41,199 performance share units (“PSUs”) to our non-employee directors and executive officers at an estimate fair value of $227.94 per share on the award date. All PSUs are performance-based and vest, if at all, after the conclusion of the three-year performance period. The number of PSUs that ultimately vest is based 50% on the growth in our diluted earnings per share and 50% on our relative total shareholder return over the vesting period. Additionally, we awarded 70,976 restricted stock units (“RSUs”) to our non-employee directors, executive officers and employees at a fair value of $188.32 per s hare on the award date. All exec

Earnings per Share ("EPS")

Earnings per Share ("EPS")	3 Months Ended
	Jan. 02, 2022
Earnings Per Share [Abstract]
Earnings per Share ("EPS")	Earnings per Share (“EPS”) Basic EPS is computed by dividing net income available to common stockholders by the weighted-average number of common shares outstanding, less unvested restricted stock for the period. Diluted EPS is computed by dividing net income by the weighted-average number of common shares outstanding and dilutive potential common shares for the period. Potential common shares include the weighted-average dilutive effects of outstanding stock options and unvested restricted stock using the treasury stock method. The following table presents the number of weighted-average shares used to compute basic and diluted EPS: Three Months Ended January 2, December 27, (in thousands, except per share data) Net income attributable to Tetra Tech $ 68,489 $ 52,436 Weighted-average common shares outstanding – basic 53,937 53,927 Effect of dilutive stock options and unvested restricted stock 640 710 Weighted-average common shares outstanding – diluted 54,577 54,637 Earnings per share attributable to Tetra Tech: Basic $ 1.27 $ 0.97 Diluted $ 1.25 $ 0.96

Income Taxes

Income Taxes	3 Months Ended
	Jan. 02, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective tax rates for the first three months of fiscal 2022 and 2021 were 18.8% and 17.0%, respectively. Income tax expense was reduced b y $4.5 million and $6.1 million of excess tax benefits on share-based payments in the first three months of fiscal 2022 and 2021, respectively. Excluding the impact of the excess tax benefits on share-based payments, our effective tax rates in the first three months fiscal 2022 and 2021 were 24.1% an d 26.8%, r espectively. As of January 2, 2022 and October 3, 2021, the liability for income taxes associated with uncertain tax positions was $13.4 million a nd $14.1 million, respectively. Th ese uncertain tax positions substantially relate to ongoing examinations. It is reasonably possible that these examinations will be resolved within the next 12 months. These liabilities represent our current estimates of the additional tax liabilities that we may be assessed when the related audits are concluded. If these audits are resolved in a manner more unfavorable than our current expectations, our additional tax liabilities could be materially higher than the amounts currently recorded resulting in additional tax expense.

Reportable Segments

Reportable Segments	3 Months Ended
	Jan. 02, 2022
Segment Reporting [Abstract]
Reportable Segments	Reportable Segments We manage our operations under two reportable segments. Our GSG reportable segment primarily includes activities with U.S. government clients (federal, state and local) and all activities with development agencies worldwide. Our CIG reportable segment primarily includes activities with U.S. commercial clients and international clients other than development agencies. Additionally , we continue to report the results of the wind-down of our non-core construction activities in the RCM reportable segment. There has been no remaining backlog for RCM since fiscal 2018 as the projects were complete. GSG provides high-end consulting and engineering services primarily to U.S. government clients (federal, state and local) and development agencies worldwide. GSG supports U.S. government civilian and defense agencies with services in water, environment, sustainable infrastructure, information technology, and disaster management. GSG also provides engineering design services for U.S. municipal and commercial clients, especially in water infrastructure, solid waste, and high-end sustainable infrastructure designs. GSG also leads our support for development agencies worldwide, especially in the United States, United Kingdom, and Australia. CIG primarily provides high-end consulting and engineering services to U.S. commercial clients, and international clients that include both commercial and government sectors. CIG supports commercial clients across the Fortun e 500, renewable energy, industrial, high performance buildings, and aerospace markets. CIG also provides sustainable infrastructure and related environmental, engineering and project management services to commercial and local government clients across Canada, in Asia Pacific (primarily Australia and New Zealand), the United Kingdom, as well as Brazil and Chile. Beginning in fiscal 2022, we aligned our operations to better serve our clients and markets, and created a new HPB division in our CIG reportable segment. As a result, we transferred some related operations in our GSG reportable segment to our CIG reportable segment. Accordingly, related balances in our segment reporting for the first quarter of fiscal 2021 have been reclassified to conform to the current year presentation. Management evaluates th e performance of these reportable segments based upon their respective segment operating income before the effect of amortization expense related to acquisitions, and other unallocated corporate expenses. We account for inter-segment revenues and transfers as if they were to third parties; that is, by applying a negotiated fee onto the costs of the services performed. All significant intercompany balances and transactions are eliminated in consolidation. The following tables summarize financial information regarding our reportable segments: Three Months Ended January 2, December 27, (in thousands) Revenue GSG $ 456,099 $ 424,663 CIG 416,286 356,526 Elimination of inter-segment revenue (13,875) (16,085) Total revenue $ 858,510 $ 765,104 Income from operations GSG $ 51,179 $ 42,695 CIG 45,308 34,563 Corporate (1) (9,267) (11,006) Total income from operations $ 87,220 $ 66,252 (1) Includes amortization of intangibles, other costs and other income not allocable to our reportable segments. Balance at January 2, October 3, (in thousands) Total Assets GSG $ 575,206 $ 545,533 CIG 703,777 698,916 RCM 11,316 11,360 Corporate (1) 1,350,157 1,320,753 Total assets $ 2,640,456 $ 2,576,562 (1) Corporate assets consist of intercompany eliminations and assets not allocated to our reportable segments including goo dwill, intangible assets, deferred income taxes and certain other assets

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Jan. 02, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The fair value of long-term debt was determined using the present value of future cash flows based on the borrowing rates currently available for debt with similar terms and maturities (Level 2 measurement, as described in “Critical Accounting Policies and Estimates” in our Annual Report on Form 10-K for the fiscal year ended October 3, 2021). The carrying value of our long-term debt approximated fair value at January 2, 2022 and October 3, 2021. At January 2, 2022, we had borrowings o f $259.4 million ou tstanding under our Amended Credit Agreement, which were used to fund business acquisitions, working capital needs, stock repurchases, dividends, capital expenditures and contingent earn-outs.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Jan. 02, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We often use certain interest rate derivative contracts to hedge interest rate exposures on our variable rate debt. Also, we may enter in foreign currency derivative contracts with financial institutions to reduce the risk that cash flows and earnings could adversely be affected by foreign currency exchange rate fluctuations. Our hedging program is not designated for trading or speculative purposes. We recognize derivative instruments as either assets or liabilities on the accompanying consolidated balance sheets at fair value. We record changes in the fair value (i.e., gains or losses) of the derivatives that have been designated as cash flow hedges in our consolidated balance sheets as accumulated other comprehensive income, and in our consolidated statements of income for those derivatives designated as fair value hedges. The derivative contracts to hedge interest exposure are categorized within Level 2 of the fair value hierarchy. In fiscal 2018, we entere d into five interest rate swap agreements that we designated as cash flow hedges to fix the interest rate on the borrowings under our term loan facility. As of January 2, 2022, the notional principal of our outstanding interest swap agreements was $209.4 million ($41.9 million each.) The interest rate swaps have a fixed interest rate of 2.79% and expire in July 2023 for all five agreements. At January 2, 2022 and October 3, 2021, the fair value of the effective portion of our interest rate swap agreements designated as cash flow hedges before tax effect was $(6.7) million and $(9.4) million, which were reported in "Other current liabilities" on our consolidated balance sheets. Additionally, the related gains of $2.7 million for the three months ended January 2, 2022, compared to related gains of $1.5 million for the prior-year period, were recognized and reported on our consolidated statements of comprehensive income. We expect to reclassify $4.6 million from accumulated other comprehensive loss to interest expense within the next twelve months. There were no other derivative instruments designated as hedging instruments for the first three months of fiscal 2022.

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income	3 Months Ended
	Jan. 02, 2022
Equity [Abstract]
Reclassifications Out of Accumulated Other Comprehensive Income	Reclassifications Out of Accumulated Other Comprehensive Income The accumulated balances and activities for the three months ended January 2, 2022 and December 27, 2020 related to reclassifications out of accumulated other comprehensive income are summarized as follows: Three Months Ended Foreign Gain (Loss) Accumulated Other Comprehensive Income (Loss) (in thousands) Balance at September 27, 2020 $ (146,275) $ (15,511) $ (161,786) Other comprehensive income before reclassifications 32,391 2,978 35,369 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — (1,502) (1,502) Net current-period other comprehensive income 32,391 1,476 33,867 Balance at December 27, 2020 $ (113,884) $ (14,035) $ (127,919) Balance at October 3, 2021 $ (115,634) $ (9,394) $ (125,028) Other comprehensive income (loss) before reclassifications (686) 4,032 3,346 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — (1,366) (1,366) Net current-period other comprehensive income (loss) (686) 2,666 1,980 Balance at January 2, 2022 $ (116,320) $ (6,728) $ (123,048) (1) This accumulated other comprehensive component is reclassified to “Interest expense” in our consolidated statements of income. See Note 14 , “Derivative Financial Instruments”, for more information.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Jan. 02, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We are subject to certain claims and lawsuits typically filed against the consulting and engineering profession, alleging primarily professional errors or omissions. We carry professional liability insurance, subject to certain deductibles and policy limits, against such claims. However, in some actions, parties are seeking damages that exceed our insurance coverage or for which we are not insured. While management does not believe that the resolution of these claims will have a material adverse effect, individually or in aggregate, on our financial position, results of operations or cash flows, management acknowledges the uncertainty surrounding the ultimate resolution of these matters. On July 15, 2019, following an initial January 14, 2019 filing, the Civil Division of the United States Attorney's Office filed an amended complaint in intervention in three qui tam actions filed against our subsidiary, Tetra Tech EC, Inc. ("TtEC"), in the U.S. District Court for the Northern District of California. The complaint alleges False Claims Act violations and breach

Related Party Transactions

Related Party Transactions	3 Months Ended
	Jan. 02, 2022
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions We often provide services to unconsolidated joint ventures. Our revenue related to services we provided to unconsolidated joint ventures for the first quarter of fiscal 2022 and 2021 was approximatel y $26 million and $22 million, respectively. Related reimbursable costs for the first quarter of fiscal 2022 and 2021 were $25 million and $21 million, respectively. Our consolidated balance sheets also included the following amounts related to these services: Balance at January 2, October 3, 2021 (in thousands) Accounts receivable, net $ 16,323 $ 19,082 Contract assets 4,126 5,092 Contract liabilities 3,978 3,026

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Jan. 02, 2022
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2019-12, which simplifies the accounting for income taxes by removing certain exceptions to general principles in Topic 740 and amending certain existing guidance for clarity . We adopted this guidance in the first quarter of fiscal 2022, and the adoption did not have an impact on our consolidated financial statements. In May 2020, the Securities and Exchange Commission issued guidance amending certain financial disclosures about acquired and disposed businesses. The amendments are designed to assist registrants in making more meaningful determinations of whether a subsidiary or an acquired or disposed business is significant, and to improve the related disclosure requirements. We adopted this guidance in the first quarter of fiscal 2022, and the adoption did not have an impact on our consolidated financial statements. In October 2021, the FASB issued ASU 2021-08, which requires the recognition and measurement of contract assets and contract liabilities acquired in a business combination in accordance with Accounting Standards Codification Topic 606, "Revenue from Contracts with Customers" ("ASC 606"). Considerations to determine the amount of contract assets and contract liabilities to record at the acquisition date include the terms of the acquired contract, such as timing of payment, identification of each performance obligation in the contract and allocation of the contract transaction price to each identified performance obligation on a relative standalone selling price basis as of contract inception. ASU 2021-08 is effective for us beginning in the first quarter of fiscal 2023. ASU 2021-08 should be applied prospectively for acquisitions occurring on or after the effective date of the amendments. Early adoption of the proposed amendments would be permitted, including adoption in an interim period. We are currently assessing the impact this standard will have on our consolidated financial statements. In November 2021, the FASB issued ASU 2021-10, Government Assistance (Topic 832), which requires disclosures for transactions with a government authority that are accounted for by applying a grant or contribution model by analogy, including (1) the types of transactions, (2) the accounting for those transactions, and (3) the effect of those transactions on an entity's financial statements. ASU 2021-10 is effective for us beginning in the first quarter of fiscal 2023, with early adoption permitted. This guidance should be applied prospectively to all transactions that are reflected in the financial statements at the date of initial application and to new transactions that are entered into after that date, or retrospectively. We do not expect the adoption of this guidance to have an impact on our consolidated financial statements.
Revenue and Contract Assets and Contract Liabilities	We invoice customers based on the contractual terms of each contract. However, the timing of revenue recognition may differ from the timing of invoice issuance. Contract assets represent revenue recognized in excess of the amounts for which we have the contractual right to bill our customers. Such amounts are recoverable from customers based upon various measures of performance, including achievement of certain milestones or completion of a contract. In addition, many of our time and materials arrangements are billed in arrears pursuant to contract terms that are standard within the industry, resulting in contract assets and/or unbilled receivables being recorded, as revenue is recognized in advance of billings. Contract retentions, included in contract assets, represent amounts withheld by clients until certain conditions are met or the project is completed, which may extend beyond one year. Our RUPO represents a measure of the total dollar value of work to be performed on contracts awarded and in progress. We h ad $3.4 billion of RUPO as of January 2, 2022. RUPO increases with awards from new contracts or additions on existing contracts and decreases as work is performed and revenue is recognized on existing contracts. RUPO may also decrease when projects are canceled or modified in scope. We include a contract within our RUPO when the contract is awarded and an agreement on contract terms has been reached.
Accounts Receivable, Net	Billed accounts receivable represent amounts billed to clients that have not been collected. Unbilled accounts receivable, which represent an unconditional right to payment subject only to the passage of time, include unbilled amounts typically resulting from revenue recognized but not yet billed pursuant to contract terms or billed after the period end date. Substantially all of our unbilled receivables at January 2, 2022 are expected to be billed and collecte d within 12 months. The allowance for doubtful accounts represents amounts that are expected to become uncollectible or unrealizable in the future. We determine an estimated allowance for uncollectible accounts based on management's consideration of trends in the actual and forecasted credit quality of our clients, including delinquency and payment history; type of client, such as a government agency or a commercial sector client; and general economic and industry conditions, including the potential impacts of the coronavirus disease 2019 ("COVID-19") pandemic, that may affect our clients' ability to pay. We regularly evaluate all unsettled claim amounts and record appropriate adjustme nts to revenue when it is probable that the claim will result in a different contract value than the amount previously estimated.

Revenue and Contract Balances (

Revenue and Contract Balances (Tables)	3 Months Ended
	Jan. 02, 2022
Revenue from Contract with Customer [Abstract]
Summary of revenue disaggregated by client sector and contract type	The following tables present revenue disaggregated by client sector and contract type: Three Months Ended January 2, December 27, (in thousands) Client Sector: U.S. state and local government $ 159,008 $ 125,008 U.S. federal government (1) 266,797 265,873 U.S. commercial 176,904 157,787 International (2) 255,801 216,436 Total $ 858,510 $ 765,104 Contract Type: Fixed-price $ 331,248 $ 274,406 Time-and-materials 395,648 355,270 Cost-plus 131,614 135,428 Total $ 858,510 $ 765,104 (1) Includes revenue generated under U.S. federal government contracts performed outside the United States. (2) Includes revenue generated from foreign operations, primarily in Canada, Australia, the United Kingdom, and revenue generated from non-U.S. clients.
Summary of net contract assets/liabilities	Net contract assets/liabilities consisted of the following: Balance at January 2, October 3, 2021 (in thousands) Contract assets (1) $ 98,439 $ 103,784 Contract liabilities (219,519) (190,403) Net contract liabilities $ (121,080) $ (86,619) (1) Inclu des $13.5 million and $12.2 million
Components of net accounts receivable	Net accounts receivable consisted of the following: Balance at January 2, October 3, (in thousands) Billed $ 441,652 $ 432,814 Unbilled 259,918 240,536 Total accounts receivable 701,570 673,350 Allowance for doubtful accounts (4,984) (4,352) Total accounts receivable, net $ 696,586 $ 668,998
Remaining performance obligation, expected timing	We expect to satisfy our RUPO as of January 2, 2022 over the following periods: Amount (in thousands) Within 12 months $ 2,042,908 Beyond 1,392,475 Total $ 3,435,383

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Jan. 02, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of changes in the carrying value of goodwill	The following table summarizes the changes in the carrying value of goodwill by reportable segment: GSG CIG Total (in thousands) Balance at October 3, 2021 $ 538,433 $ 570,145 $ 1,108,578 Goodwill reallocation (51,497) 51,497 — Acquisition activity 14,671 — 14,671 Translation and adjustments 44 (233) (189) Balance at January 2, 2022 $ 501,651 $ 621,409 $ 1,123,060
Summary of acquired identifiable intangible assets with finite useful lives	The following table presents the gross amount and accumulated amortization of our acquired identifiable intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets: Period Ended January 2, 2022 October 3, 2021 Weighted- Gross Accumulated Net Amount Gross Accumulated Net Amount ($ in thousands) Client relations 6.4 $ 43,646 $ (18,723) $ 24,923 $ 69,455 $ (43,984) $ 25,471 Backlog 1.2 32,113 (28,573) 3,540 34,577 (30,670) 3,907 Technology and trade names 4.3 14,936 (6,864) 8,072 14,939 (6,327) 8,612 Total $ 90,695 $ (54,160) $ 36,535 $ 118,971 $ (80,981) $ 37,990
Estimated amortization expense for the remainder of the fiscal year and the succeeding years	Estimated amortization expense for the remainder of fiscal 2022 and succeeding years is as follows: Amount (in thousands) 2022 $ 7,733 2023 7,859 2024 5,193 2025 4,359 2026 3,963 Beyond 7,428 Total $ 36,535

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Jan. 02, 2022
Property, Plant and Equipment [Abstract]
Schedule of components of property and equipment	Property and equipment consisted of the following: Balance at January 2, October 3, (in thousands) Equipment, furniture and fixtures $ 95,228 $ 94,780 Leasehold improvements 36,472 36,462 Total property and equipment 131,700 131,242 Accumulated depreciation (96,272) (93,509) Property and equipment, net $ 35,428 $ 37,733

Stock Repurchase and Dividends

Stock Repurchase and Dividends (Tables)	3 Months Ended
	Jan. 02, 2022
Stock Repurchase And Dividends [Abstract]
Summary of dividends declared and paid	The following table presents dividends declared and paid in the first quarters of fiscal 2022 and 2021: Declare Date Dividend Paid Per Share Record Date Payment Date Dividend Paid November 15, 2021 $ 0.20 December 2, 2021 December 20, 2021 $ 10,793 November 9, 2020 $ 0.17 November 30, 2020 December 11, 2020 $ 9,198

Leases (Tables)

Leases (Tables)	3 Months Ended
	Jan. 02, 2022
Leases [Abstract]
Summary of components of lease cost	The components of lease costs are as follows: Three Months Ended January 2, December 27, (in thousands) Operating lease cost $ 21,751 $ 22,069 Sublease income (125) (29) Total lease cost $ 21,626 $ 22,040 Supplemental cash flow information related to leases is as follows: Three Months Ended January 2, December 27, (in thousands) Operating cash flows for operating leases $ 17,519 $ 18,800 Right-of-use assets obtained in exchange for new operating lease liabilities $ 12,347 $ 10,293
Summary of supplemental balance sheet and other information	Supplemental balance sheet and other information related to leases are as follows: Balance at January 2, 2022 October 3, 2021 (in thousands) Operating leases: Right-of-use assets $ 212,018 $ 215,422 Lease liabilities: Current 65,185 67,452 Long-term 172,795 174,285 Total operating lease liabilities $ 237,980 $ 241,737 Weighted-average remaining lease term: Operating leases 5 years 5 years Weighted-average discount rate: Operating leases 2.1 % 2.2 %
Summary of maturity of future undiscounted cash flows associated with operating lease liabilities	A maturity analysis of the future undiscounted cash flows associated with our operating lease liabilities at January 2, 2022 is as follows: Amount (in thousands) 2022 $ 53,596 2023 57,830 2024 42,775 2025 31,876 2026 21,407 Beyond 45,581 Total lease payments 253,065 Less: imputed interest (15,085) Total present value of lease liabilities $ 237,980

Earnings per Share ("EPS") (Tab

Earnings per Share ("EPS") (Tables)	3 Months Ended
	Jan. 02, 2022
Earnings Per Share [Abstract]
Schedule of number of weighted-average shares used to compute basic and diluted EPS	The following table presents the number of weighted-average shares used to compute basic and diluted EPS: Three Months Ended January 2, December 27, (in thousands, except per share data) Net income attributable to Tetra Tech $ 68,489 $ 52,436 Weighted-average common shares outstanding – basic 53,937 53,927 Effect of dilutive stock options and unvested restricted stock 640 710 Weighted-average common shares outstanding – diluted 54,577 54,637 Earnings per share attributable to Tetra Tech: Basic $ 1.27 $ 0.97 Diluted $ 1.25 $ 0.96

Reportable Segments (Tables)

Reportable Segments (Tables)	3 Months Ended
	Jan. 02, 2022
Segment Reporting [Abstract]
Summarized financial information of reportable segments	The following tables summarize financial information regarding our reportable segments: Three Months Ended January 2, December 27, (in thousands) Revenue GSG $ 456,099 $ 424,663 CIG 416,286 356,526 Elimination of inter-segment revenue (13,875) (16,085) Total revenue $ 858,510 $ 765,104 Income from operations GSG $ 51,179 $ 42,695 CIG 45,308 34,563 Corporate (1) (9,267) (11,006) Total income from operations $ 87,220 $ 66,252 (1) Includes amortization of intangibles, other costs and other income not allocable to our reportable segments. Balance at January 2, October 3, (in thousands) Total Assets GSG $ 575,206 $ 545,533 CIG 703,777 698,916 RCM 11,316 11,360 Corporate (1) 1,350,157 1,320,753 Total assets $ 2,640,456 $ 2,576,562 (1) Corporate assets consist of intercompany eliminations and assets not allocated to our reportable segments including goo dwill, intangible assets, deferred income taxes and certain other assets

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Jan. 02, 2022
Equity [Abstract]
Summary of reclassifications out of accumulated other comprehensive income	The accumulated balances and activities for the three months ended January 2, 2022 and December 27, 2020 related to reclassifications out of accumulated other comprehensive income are summarized as follows: Three Months Ended Foreign Gain (Loss) Accumulated Other Comprehensive Income (Loss) (in thousands) Balance at September 27, 2020 $ (146,275) $ (15,511) $ (161,786) Other comprehensive income before reclassifications 32,391 2,978 35,369 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — (1,502) (1,502) Net current-period other comprehensive income 32,391 1,476 33,867 Balance at December 27, 2020 $ (113,884) $ (14,035) $ (127,919) Balance at October 3, 2021 $ (115,634) $ (9,394) $ (125,028) Other comprehensive income (loss) before reclassifications (686) 4,032 3,346 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — (1,366) (1,366) Net current-period other comprehensive income (loss) (686) 2,666 1,980 Balance at January 2, 2022 $ (116,320) $ (6,728) $ (123,048) (1) This accumulated other comprehensive component is reclassified to “Interest expense” in our consolidated statements of income. See Note 14 , “Derivative Financial Instruments”, for more information.

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Jan. 02, 2022
Related Party Transactions [Abstract]
Schedule of related party transactions	Our consolidated balance sheets also included the following amounts related to these services: Balance at January 2, October 3, 2021 (in thousands) Accounts receivable, net $ 16,323 $ 19,082 Contract assets 4,126 5,092 Contract liabilities 3,978 3,026

Revenue and Contract Balances -

Revenue and Contract Balances - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 858,510	$ 765,104
Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	331,248	274,406
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue	395,648	355,270
Cost-plus
Disaggregation of Revenue [Line Items]
Revenue	131,614	135,428
U.S. state and local government
Disaggregation of Revenue [Line Items]
Revenue	159,008	125,008
U.S. federal government
Disaggregation of Revenue [Line Items]
Revenue	266,797	265,873
U.S. commercial
Disaggregation of Revenue [Line Items]
Revenue	176,904	157,787
International
Disaggregation of Revenue [Line Items]
Revenue	$ 255,801	$ 216,436

Revenue and Contract Balances_2

Revenue and Contract Balances - Summary of Contract Liabilities/Assets (Details) - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Disaggregation of Revenue [Line Items]
Contract assets	$ 98,439	$ 103,784
Contract liabilities	(219,519)	(190,403)
Net contract liabilities	(121,080)	(86,619)
Contract Retentions
Disaggregation of Revenue [Line Items]
Contract assets	$ 13,500	$ 12,200

Revenue and Contract Balances_3

Revenue and Contract Balances - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020	Oct. 03, 2021
Revenue from Contract with Customer [Abstract]
Contract liability revenue recognized during the period	$ 63,000	$ 60,000
Net favorable (unfavorable) revenue and operating income adjustments	2,800	$ 0
Liabilities for anticipated losses	14,200		$ 12,700
Estimated cost to complete the related contracts	$ 116,000		104,000
Period for billing and collecting unbilled receivables	12 months
Unbilled accounts receivable related to claims and requests for equitable adjustment on contracts	$ 11,000		$ 11,000
Remaining unsatisfied performance obligation	$ 3,435,383
Remaining performance obligation, termination notice period one	30 days
Remaining performance obligation, termination notice period two	60 days
Remaining performance obligation, termination notice period three	90 days

Revenue and Contract Balances_4

Revenue and Contract Balances - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Revenue from Contract with Customer [Abstract]
Billed	$ 441,652	$ 432,814
Unbilled	259,918	240,536
Total accounts receivable	701,570	673,350
Allowance for doubtful accounts	(4,984)	(4,352)
Total accounts receivable, net	$ 696,586	$ 668,998

Revenue and Contract Balances_5

Revenue and Contract Balances - Remaining Unsatisfied Performance Obligations (Details) $ in Thousands	Jan. 02, 2022USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining unsatisfied performance obligation	$ 3,435,383
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-03
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining unsatisfied performance obligation	$ 2,042,908
Remaining unsatisfied performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-02
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining unsatisfied performance obligation	$ 1,392,475
Remaining unsatisfied performance obligation, expected timing of satisfaction

Acquisitions (Details)

Acquisitions (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jan. 02, 2022USD ($)	Oct. 03, 2021USD ($)employee
Business Acquisition [Line Items]
Contingent earn-out liability	$ 65.8
Minimum
Business Acquisition [Line Items]
Significant unobservable input, earn-out period	3 years
Minimum | Existing customer contracts
Business Acquisition [Line Items]
Useful life of intangible assets	1 year
Minimum | Trade names
Business Acquisition [Line Items]
Useful life of intangible assets	3 years
Maximum
Business Acquisition [Line Items]
Significant unobservable input, earn-out period	5 years
Maximum | Existing customer contracts
Business Acquisition [Line Items]
Useful life of intangible assets	10 years
Maximum | Trade names
Business Acquisition [Line Items]
Useful life of intangible assets	5 years
Hoare Lea
Business Acquisition [Line Items]
Number of employees | employee		900
Business acquisitions
Business Acquisition [Line Items]
Fair value of acquisition purchase price		$ 151.7
Initial cash payments		101.4
Contingent earn-out liability		50.3
Aggregate maximum of contingent consideration		$ 74
Business acquisitions | Minimum
Business Acquisition [Line Items]
Earn-out period		3 years
Business acquisitions | Maximum
Business Acquisition [Line Items]
Earn-out period		4 years
All acquisitions
Business Acquisition [Line Items]
Aggregate maximum of contingent consideration	$ 119.4

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended
	Jan. 02, 2022USD ($)
Goodwill
Balance at beginning of the period	$ 1,108,578
Goodwill reallocation	0
Acquisition activity	14,671
Translation and adjustments	(189)
Balance at end of the period	1,123,060
GSG
Goodwill
Balance at beginning of the period	538,433
Goodwill reallocation	(51,497)
Acquisition activity	14,671
Translation and adjustments	44
Balance at end of the period	501,651
CIG
Goodwill
Balance at beginning of the period	570,145
Goodwill reallocation	51,497
Acquisition activity	0
Translation and adjustments	(233)
Balance at end of the period	$ 621,409

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	Jun. 28, 2021	Jan. 02, 2022	Dec. 27, 2020	Oct. 04, 2021	Oct. 03, 2021
Goodwill [Line Items]
Impairment of goodwill	$ 0
Percentage of excess of fair value over carrying value (less than)	150.00%			150.00%
Amortization expense		$ 2,700,000	$ 3,400,000
GSG
Goodwill [Line Items]
Gross amounts of goodwill		519,400,000			$ 556,100,000
Accumulated impairment		17,700,000			17,700,000
CIG
Goodwill [Line Items]
Gross amounts of goodwill		742,900,000			691,600,000
Accumulated impairment		$ 121,500,000			$ 121,500,000

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Gross Amount and Accumulated Amortization of Acquired Finite-lived Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Oct. 03, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 90,695	$ 118,971
Accumulated Amortization	(54,160)	(80,981)
Net Amount	$ 36,535	37,990
Client relations
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	6 years 4 months 24 days
Gross Amount	$ 43,646	69,455
Accumulated Amortization	(18,723)	(43,984)
Net Amount	$ 24,923	25,471
Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	1 year 2 months 12 days
Gross Amount	$ 32,113	34,577
Accumulated Amortization	(28,573)	(30,670)
Net Amount	$ 3,540	3,907
Technology and trade names
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	4 years 3 months 18 days
Gross Amount	$ 14,936	14,939
Accumulated Amortization	(6,864)	(6,327)
Net Amount	$ 8,072	$ 8,612

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 7,733
2023	7,859
2024	5,193
2025	4,359
2026	3,963
Beyond	7,428
Net Amount	$ 36,535	$ 37,990

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020	Oct. 03, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 131,700		$ 131,242
Accumulated depreciation	(96,272)		(93,509)
Property and equipment, net	35,428		37,733
Depreciation expense related to property and equipment	3,400	$ 2,900
Equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	95,228		94,780
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 36,472		$ 36,462

Stock Repurchase and Dividend_2

Stock Repurchase and Dividends - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 25, 2022	Jan. 31, 2022	Dec. 20, 2021	Dec. 11, 2020	Jan. 02, 2022	Dec. 27, 2020	Oct. 05, 2021	Oct. 03, 2021
Subsequent Event [Line Items]
Remaining authorized amount under share repurchase program					$ 497.8			$ 147.8
Shares repurchased (in shares)					290,196
Average price (in dollars per share)					$ 172.30
Total cost					$ 50
Dividend paid per share (in dollars per share)			$ 0.20	$ 0.17	$ 0.20	$ 0.17
Subsequent Event
Subsequent Event [Line Items]
Quarterly cash dividend declared (in dollars per share)		$ 0.20
Forecast
Subsequent Event [Line Items]
Dividend paid per share (in dollars per share)	$ 0.20
October 2021 Stock Repurchase Program
Subsequent Event [Line Items]
Maximum repurchase amount under stock repurchase program							$ 400

Stock Repurchase and Dividend_3

Stock Repurchase and Dividends - Schedule of Dividends Declared and Paid (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 20, 2021	Dec. 11, 2020	Jan. 02, 2022	Dec. 27, 2020
Stock Repurchase And Dividends [Abstract]
Dividend paid per share (in dollars per share)	$ 0.20	$ 0.17	$ 0.20	$ 0.17
Dividend Paid	$ 10,793	$ 9,198

Leases - Narrative (Details)

Leases - Narrative (Details)	Jan. 02, 2022
Lessee, Lease, Description [Line Items]
Renewal term (up to)	5 years
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 month
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	12 years

Leases - Components of Lease Co

Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Leases [Abstract]
Operating lease cost	$ 21,751	$ 22,069
Sublease income	(125)	(29)
Total lease cost	$ 21,626	$ 22,040

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Leases [Abstract]
Operating cash flows for operating leases	$ 17,519	$ 18,800
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 12,347	$ 10,293

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet and Other Information (Details) - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Operating leases:
Right-of-use assets	$ 212,018	$ 215,422
Lease liabilities:
Current	65,185	67,452
Long-term	172,795	174,285
Total operating lease liabilities	$ 237,980	$ 241,737
Weighted-average remaining lease term:
Operating leases	5 years	5 years
Weighted-average discount rate:
Operating leases	2.10%	2.20%

Leases - Maturity Analysis of t

Leases - Maturity Analysis of the Future Undiscounted Cash Flows of Operating and Finance Lease Liabilities (Details) - USD ($) $ in Thousands	Jan. 02, 2022	Oct. 03, 2021
Leases [Abstract]
2022	$ 53,596
2023	57,830
2024	42,775
2025	31,876
2026	21,407
Beyond	45,581
Total lease payments	253,065
Less: imputed interest	(15,085)
Total present value of lease liabilities	$ 237,980	$ 241,737

Stockholders' Equity and Stoc_2

Stockholders' Equity and Stock Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5.8	$ 4.9
PSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	41,199
Fair value of awards granted (in dollars per share)	$ 227.94
Vesting period	3 years
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%
RSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	70,976
Fair value of awards granted (in dollars per share)	$ 188.32
RSU's | Executive officers and employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
RSU's | Non-employee director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Earnings per Share ("EPS") (Det

Earnings per Share ("EPS") (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Earnings Per Share [Abstract]
Net income attributable to Tetra Tech	$ 68,489	$ 52,436
Weighted-average common shares outstanding – basic (in shares)	53,937	53,927
Effect of dilutive stock options and unvested restricted stock (in shares)	640	710
Weighted-average common stock outstanding – diluted (in shares)	54,577	54,637
Earnings per share attributable to Tetra Tech:
Basic (in dollars per share)	$ 1.27	$ 0.97
Diluted (in dollars per share)	$ 1.25	$ 0.96

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020	Oct. 03, 2021
Income Tax Disclosure [Abstract]
Effective tax rate	18.80%	17.00%
Reduction in income tax expense due to excess tax benefits on share-based payments	$ 4.5	$ 6.1
Effective tax rate, excluding excess tax benefits on share-based payments	24.10%	26.80%
Liability for uncertain tax positions	$ 13.4		$ 14.1

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended
	Jan. 02, 2022USD ($)segment	Dec. 27, 2020USD ($)	Oct. 03, 2021USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Revenue	$ 858,510	$ 765,104
Income from operations	87,220	66,252
Total Assets	2,640,456		$ 2,576,562
Operating segments | GSG
Segment Reporting Information [Line Items]
Revenue	456,099	424,663
Income from operations	51,179	42,695
Total Assets	575,206		545,533
Operating segments | CIG
Segment Reporting Information [Line Items]
Revenue	416,286	356,526
Income from operations	45,308	34,563
Total Assets	703,777		698,916
Operating segments | RCM
Segment Reporting Information [Line Items]
Total Assets	11,316		11,360
Elimination of inter-segment revenue
Segment Reporting Information [Line Items]
Revenue	(13,875)	(16,085)
Corporate
Segment Reporting Information [Line Items]
Income from operations	(9,267)	$ (11,006)
Total Assets	$ 1,350,157		$ 1,320,753

Fair Value Measurements (Detail

Fair Value Measurements (Details) $ in Millions	Jan. 02, 2022USD ($)
Amended Credit Agreement
Debt Instrument [Line Items]
Amount outstanding under credit facility	$ 259.4

Derivative Financial Instrume_2

Derivative Financial Instruments (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Jan. 02, 2022USD ($)	Dec. 27, 2020USD ($)	Sep. 30, 2018agreement	Oct. 03, 2021USD ($)
Derivative [Line Items]
Gains (losses) on cash flow hedges recognized in comprehensive income	$ 2,666	$ 1,476
Interest Rate Swap | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Number of derivative agreements | agreement			5
Notional amount	$ 209,400
Fixed rate	2.79%
Loss to be reclassified during next twelve months	$ 4,600
Interest Rate Swap | Designated as cash flow hedges | Derivatives designated as hedging instruments | Other current liabilities
Derivative [Line Items]
Fair value of interest rate swap agreements	(6,700)			$ (9,400)
Interest Rate Swap 1 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	41,900
Interest Rate Swap 2 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	41,900
Interest Rate Swap 3 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	41,900
Interest Rate Swap 4 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	41,900
Interest Rate Swap 5 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	$ 41,900

Reclassifications Out of Accu_3

Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	$ 1,234,291	$ 1,037,373
Amounts reclassified from accumulated other comprehensive loss
Other comprehensive income, net of tax	1,980	33,869
Ending balance	1,237,945	1,105,254
Accumulated Other Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	(125,028)	(161,786)
Other comprehensive income (loss) before reclassifications	3,346	35,369
Amounts reclassified from accumulated other comprehensive loss
Interest rate contracts, net of tax	(1,366)	(1,502)
Other comprehensive income, net of tax	1,980	33,867
Ending balance	(123,048)	(127,919)
Foreign Currency Translation Adjustments
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	(115,634)	(146,275)
Other comprehensive income (loss) before reclassifications	(686)	32,391
Amounts reclassified from accumulated other comprehensive loss
Other comprehensive income, net of tax	(686)	32,391
Ending balance	(116,320)	(113,884)
Gain (Loss) on Derivative Instruments
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	(9,394)	(15,511)
Other comprehensive income (loss) before reclassifications	4,032	2,978
Amounts reclassified from accumulated other comprehensive loss
Interest rate contracts, net of tax	(1,366)	(1,502)
Other comprehensive income, net of tax	2,666	1,476
Ending balance	$ (6,728)	$ (14,035)

Commitments and Contingencies (

Commitments and Contingencies (Details)	Jul. 15, 2019action
Commitments and Contingencies Disclosure [Abstract]
Number of qui tam actions	3

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Dec. 27, 2020	Oct. 03, 2021
Related Party Transactions [Abstract]
Related party revenues	$ 26,000	$ 22,000
Related party expenses	25,000	$ 21,000
Accounts receivable, net	16,323		$ 19,082
Contract assets	4,126		5,092
Contract liabilities	$ 3,978		$ 3,026