Tetra Tech (TTEK) 10-Q 3 Feb 23 2023 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Jan. 01, 2023	Jan. 23, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jan. 01, 2023
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		53,226,139
Entity Central Index Key	0000831641
Amendment Flag	false
Current Fiscal Year End Date	--10-01
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Current assets:
Cash and cash equivalents	$ 164,397	$ 185,094
Accounts receivable, net	795,872	755,112
Contract assets	80,903	92,405
Prepaid expenses and other current assets	193,635	125,605
Total current assets	1,234,807	1,158,216
Property and equipment, net	34,890	32,316
Right-of-use assets, operating leases	182,500	182,319
Goodwill	1,133,303	1,110,412
Intangible assets, net	27,536	29,163
Deferred tax assets	52,009	47,804
Other non-current assets	66,435	62,546
Total assets	2,731,480	2,622,776
Current liabilities:
Accounts payable	151,256	147,436
Accrued compensation	184,468	237,669
Contract liabilities	274,118	241,340
Short-term lease liabilities, operating leases	55,809	57,865
Current portion of long-term debt	12,505	12,504
Current contingent earn-out liabilities	33,701	28,797
Other current liabilities	158,758	190,406
Total current liabilities	870,615	916,017
Deferred tax liabilities	32,779	15,161
Long-term debt	234,120	246,250
Long-term lease liabilities, operating leases	148,034	146,285
Non-current contingent earn-out liabilities	35,328	36,769
Other non-current liabilities	86,637	79,157
Commitments and contingencies (Note 17)
Equity:
Preferred stock - authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at January 1, 2023 and October 2, 2022	0	0
Common stock - authorized, 150,000 shares of $0.01 par value; issued and outstanding, 53,226 and 52,981 shares at January 1, 2023 and October 2, 2022, respectively	532	530
Additional paid-in capital	3,281	0
Accumulated other comprehensive loss	(175,126)	(208,144)
Retained earnings	1,495,221	1,390,701
Tetra Tech stockholders’ equity	1,323,908	1,183,087
Noncontrolling interests	59	50
Total stockholders' equity	1,323,967	1,183,137
Total liabilities and stockholders' equity	$ 2,731,480	$ 2,622,776

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jan. 01, 2023	Oct. 02, 2022
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)	53,226,000	52,981,000
Common stock, shares outstanding (in shares)	53,226,000	52,981,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Revenue	$ 894,766	$ 858,510
Gross profit	153,246	139,766
Selling, general and administrative expenses	(56,502)	(52,546)
Acquisition and integration expenses	(3,761)	0
Contingent consideration – fair value adjustments	(933)	0
Income from operations	92,050	87,220
Interest expense, net	(5,372)	(2,904)
Other Nonoperating Income (Expense)	67,995	0
Income before income tax expense	154,673	84,316
Income tax expense	(37,958)	(15,817)
Net income	116,715	68,499
Net income attributable to noncontrolling interests	(9)	(10)
Net income attributable to Tetra Tech, basic	116,706	68,489
Net income attributable to Tetra Tech, diluted	$ 116,706	$ 68,489
Earnings per share attributable to Tetra Tech:
Basic (in dollars per share)	$ 2.20	$ 1.27
Diluted (in dollars per share)	$ 2.18	$ 1.25
Weighted-average common shares outstanding:
Basic (in shares)	53,069	53,937
Diluted (in shares)	53,529	54,577
Subcontractor costs
Cost of revenue	$ (158,204)	$ (179,177)
Other costs of revenue
Cost of revenue	$ (583,316)	$ (539,567)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 116,715	$ 68,499
Other comprehensive income, net of tax
Foreign currency translation adjustment, net of tax	33,107	(686)
Gain (loss) on cash flow hedge valuations, net of tax	(89)	2,666
Other comprehensive income, net of tax	33,018	1,980
Comprehensive income, net of tax	149,733	70,479
Comprehensive income attributable to noncontrolling interests, net of tax	9	10
Comprehensive income attributable to Tetra Tech, net of tax	$ 149,724	$ 70,469

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Cash flows from operating activities:
Net income	$ 116,715	$ 68,499
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,616	6,111
Equity in income of unconsolidated joint ventures	(1,447)	(1,440)
Distributions of earnings from unconsolidated joint ventures	1,115	842
Amortization of stock-based awards	7,184	5,828
Deferred income taxes	15,935	(878)
Fair value adjustments to contingent consideration	933	0
Fair value adjustments to foreign currency forward contract	(67,995)	0
Changes in operating assets and liabilities, net of effects of business acquisitions:
Accounts receivable and contract assets	(16,175)	(21,560)
Prepaid expenses and other assets	5,967	5,364
Accounts payable	3,820	14,056
Accrued compensation	(53,201)	(40,321)
Contract liabilities	27,769	29,227
Other liabilities	(26,432)	11,854
Income taxes receivable/payable	4,387	4,837
Net cash provided by operating activities	25,191	82,419
Cash flows from investing activities:
Payments for business acquisitions, net of cash acquired	0	(8,858)
Capital expenditures	(4,996)	(1,518)
Proceeds from sale of assets	51	3,514
Net cash used in investing activities	(4,945)	(6,862)
Cash flows from financing activities:
Proceeds from borrowings	60,889	54,989
Repayments on long-term debt	(73,125)	(3,956)
Repurchases of common stock	0	(50,000)
Taxes paid on vested restricted stock	(16,586)	(24,949)
Stock options exercised	57	960
Dividends paid	(12,186)	(10,793)
Payments of contingent earn-out liabilities	0	(1,720)
Principal payments on finance leases	(1,316)	(945)
Net cash used in financing activities	(42,267)	(36,414)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	8,695	(169)
Net increase (decrease) in cash, cash equivalents and restricted cash	(13,326)	38,974
Cash, cash equivalents and restricted cash at beginning of period	185,491	166,568
Cash, cash equivalents and restricted cash at end of period	172,165	205,542
Cash paid during the period for:
Interest	3,433	2,456
Income taxes, net of refunds received of $0.1 million and $2.3 million	14,540	11,535
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	164,397	205,542
Restricted cash	$ 7,768	$ 0

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Statement of Cash Flows [Abstract]
Income tax refunds	$ 0.1	$ 2.3

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Tetra Tech Equity	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Non-Controlling Interests
Beginning balance (in shares) at Oct. 03, 2021			53,981
Beginning balance at Oct. 03, 2021	$ 1,234,291	$ 1,234,238	$ 540	$ 0	$ (125,028)	$ 1,358,726	$ 53
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	68,499	68,489				68,489	10
Other comprehensive income	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)	(24,949)	$ 2	(18,916)		(6,035)
Stock options exercised (in shares)			20
Stock options exercised	960	960	$ 0	960
Shares issued for Employee Stock Purchase Plan (in shares)			106
Shares issued for Employee Stock Purchase Plan	12,129	12,129	$ 1	12,128
Stock repurchases (in shares)			(290)
Stock repurchases	(50,000)	(50,000)	$ (3)	0		(49,997)
Ending balance (in shares) at Jan. 02, 2022			53,999
Ending balance at Jan. 02, 2022	1,237,945	1,237,882	$ 540	0	(123,048)	1,360,390	63
Beginning balance (in shares) at Oct. 02, 2022			52,981
Beginning balance at Oct. 02, 2022	1,183,137	1,183,087	$ 530	0	(208,144)	1,390,701	50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	116,715	116,706				116,706	9
Other comprehensive income	33,018	33,018			33,018
Cash dividends per common share	(12,186)	(12,186)				(12,186)
Stock-based compensation	7,184	7,184		7,184
Restricted & performance shares released (in shares)			145
Restricted & performance shares released	(16,586)	(16,586)	$ 1	(16,587)
Stock options exercised (in shares)			2
Stock options exercised	57	57	$ 0	57
Shares issued for Employee Stock Purchase Plan (in shares)			98
Shares issued for Employee Stock Purchase Plan	12,628	12,628	$ 1	12,627
Ending balance (in shares) at Jan. 01, 2023			53,226
Ending balance at Jan. 01, 2023	$ 1,323,967	$ 1,323,908	$ 532	$ 3,281	$ (175,126)	$ 1,495,221	$ 59

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares			3 Months Ended
	Dec. 09, 2022	Dec. 20, 2021	Jan. 01, 2023	Jan. 02, 2022
Statement of Stockholders' Equity [Abstract]
Dividend paid per share (in dollars per share)	$ 0.23	$ 0.20	$ 0.23	$ 0.20

Basis of Presentation

Basis of Presentation	3 Months Ended
	Jan. 01, 2023
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 2, 2022. 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 fiscal year or for future fiscal yea rs. Certain prior year amounts have been reclassified to conform to the current year presentation.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Jan. 01, 2023
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2021, the Financial Accounting Standards Board ("FASB") issued ASU 2021-10, Government Assistance (Topic 832), which requires annual 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 was effective for us beginning in the first quarter of fiscal 2023. In fiscal 2020, the Canadian federal government implemented the Canadian Emergency Wage Subsidy ("CEWS") program in response to the negative impact of the coronavirus disease 2019 (" COVID-19") pandemic on businesses operating in Canada. Our Canadian legal entities qualified for and applied for these CEWS cash benefits to partially offset the impacts of revenue reductions and on-going staffing costs. The $26.0 million total received was initially recorded in "Other current liabilities" until all potential amendments to the qualification criteria, including some that were proposed with retroactive application, were finalized in fiscal 2022. As there are no further contingencies, beginning in fiscal 2023, the amounts received will be distributed to all Canadian employees. We expect to distribute approximately $9 million in the next twelve months. Accordingly, this amount was reclassified from "Other current liabilities" to "Accrued compensation" on our consolidated balance sheet at October 2, 2022. The remaining $17.0 million, which we expect to distribute beyond one year, was reclassified to "Other non-current liabilities". We do not expect there will be any related impact to our operating income, and we have no outstanding applications for further government assistance.

Revenue and Contract Balances

Revenue and Contract Balances	3 Months Ended
	Jan. 01, 2023
Revenue from Contract with Customer [Abstract]
Revenue and Contract Balances	Revenue and Contract Balances 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 (in thousands): Three Months Ended January 1, January 2, Client Sector: U.S. federal government (1) $ 276,075 $ 266,797 U.S. state and local government 153,195 159,008 U.S. commercial 198,956 176,904 International (2) 266,540 255,801 Total $ 894,766 $ 858,510 Contract Type: Fixed-price $ 327,737 $ 331,248 Time-and-materials 420,570 395,648 Cost-plus 146,459 131,614 Total $ 894,766 $ 858,510 (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 1, 2023 and January 2, 2022. 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 (in thousands): Balance at January 1, October 2, 2022 Contract assets (1) $ 80,903 $ 92,405 Contract liabilities 274,118 241,340 Net contract liabilities $ (193,215) $ (148,935) (1) Inclu des $17.2 million and $23.3 million of contract retentions at January 1, 2023 and October 2, 2022, respectively. In the first quarters of fiscal 2023 and 2022 , we recognized revenue of approximately $81 million and $63 million, respectively, from amounts included in the contract liability balances at the end of fiscal 2022 and 20 21, respectively. We recognize revenue primarily using the cost-to-cost measure of progress method 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 $3.5 million and $2.8 million in the first quarters of fiscal 2023 and 2022, respectively. C hanges in revenue and cost estimates could also result in a projected loss, determined at the contract level, which would be recorded immediate ly in earnings. At January 1, 2023 and October 2, 2022, our consolidated balance sheets included liabilities for anticipated losses of $7.6 million and $10.0 million, respectively. The estimated cost to complete these related contracts at January 1, 2023 and October 2, 2022 was approximately $55 million and $80 million, respectively. Accounts Receivable, Net Net accounts receivable consisted of the following (in thousands): Balance at January 1, October 2, Billed $ 486,027 $ 491,700 Unbilled 313,782 267,161 Total accounts receivable 799,809 758,861 Allowance for doubtful accounts (3,937) (3,749) Total accounts receivable, net $ 795,872 $ 755,112 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 1, 2023 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. 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. There were no claims included in our total accounts receivable at January 1, 2023 and October 2, 2022. We regularly evaluate all unsettled claim amounts and record appropriate adjustments 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 2023 and 2022, 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 1, 2023 and October 2, 2022. 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 $3.8 billion of RUPO at January 1, 2023. 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 at January 1, 2023 over the following periods (in thousands): Amount Within 12 months $ 2,460,171 Beyond 1,329,949 Total $ 3,790,120

Acquisitions

Acquisitions	3 Months Ended
	Jan. 01, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisitions	Acquisitions Subsequent Event. O n January 3, 2023, we acquired Amyx, Inc. (“Amyx”), an enterprise technology services, cybersecurity and management consulting firm. Based in Reston, Virginia, Amyx, with over 500 employees, provides application modernization, cybersecurity, systems engineering, financial management, and program management support on over 30 Federal Government programs. Amyx will be included in our GSG segment. Subsequent Event. On September 23, 2022, we made an all cash offer to acquire all of the outstanding shares of RPS Group plc ("RPS"), a publicly traded company on the London Stock Exchange for 222 pence per share, through a scheme of arrangement, which was unanimously recommended by RPS's Board of Directors. On November 3, 2022, RPS's shareholders approved the scheme of arrangement. On January 19, 2023, the court sanctioned scheme of arrangement to purchase RPS was approved, and we completed the acquisition on January 23, 202 3. The total purchase price including assumed debt and transactions costs was approximately GBP 714 million. RPS employs approximately 5,000 associates in the United Kingdom, Europe, Asia Pacific and North America, delivering high-end solutions, especially in energy transformation, water and program management for government and commercial clients. Substantially all of RPS will be included in our CIG segment. T he results of these acquisitions will be included in our consolidated financial statements beginning on the respective closing dates. We are in the process of performing procedures to determine the fair value of assets acquired and liabilities assumed related to the acquisitions, and will include the preliminary purchase price allocation in our Quarterly Report on Form 10-Q for the period ending April 2, 2023. See Note 14, "Credit Facility" for additional information regarding the financing of these acquisitions. In fiscal 2022, we acquired The Integration Group of America ("TIGA"), Piteau Associates (“PAE”) and other financially immaterial acquisitions. TIGA is based in Spring, Texas and is an industry leader in process automation and system integration solutions, including customized software and platform (SaaS/PaaS) applications, advanced data analytics, cloud data integration and platform virtualization. PAE is based in Vancouver, British Columbia and is a global leader in sustainable natural resource analytics including hydrologic numerical modeling and dewatering system design. PAE is part of our CIG segment, and TIGA and other immaterial acquisitions are part of our GSG segment. The total fair value of the purchase price for all four acquisitions was $88.3 million. This amount is comprised of $44.0 million in initial cash payments made to the sellers, $2.5 million of receivables (net) related to estimated post-closing adjustments for the net assets acquired, $15.5 million payable in a promissory note issued to the sellers along with related transaction expenses of the sellers (which were subsequently paid in July 2022), and $31.3 million for the estimated fair value of contingent earn-out obligations, with a maximum of $47.0 million, based upon the achievement of specified operating income targets in each of the three Goodwill additions resulting from fiscal 2022 business combinations are primarily attributable to the significant technical expertise residing in embedded workforces that are sought out by clients, long-term management experience, the industry reputations, and the synergies expected to arise after the acquisitions in the areas of data management, digitization, modeling, water, and natural resources. 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 companies. The results of these acquisitions were included in our consolidated financial statements from their respective closing dates. These acquisitions were not considered material to our financial statements, individually or in the aggregate, to our consolidated financial statements. As a result, no pro forma information has been provided. Backlog and client relations 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 “Non-current 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. For the first quarter of fiscal 2023, we evaluated our estimates for contingent consideration liabilities for the remaining earn-out periods for each individu al 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 2023 and 2022, we had no material adjustments to our contingent earn-out liabilities in operating income. At January 1, 2023, there was a total potential maximum of $120.9 million of outstanding contingent consideration related to acquisitions. Of this amount, $69.0 million was estimated as the fair value and accrued on our consolidated balance sheet.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Jan. 01, 2023
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 (in thousands): GSG CIG Total Balance at October 2, 2022 $ 519,102 $ 591,310 $ 1,110,412 Translation adjustments 2,792 20,099 22,891 Balance at January 1, 2023 $ 521,894 $ 611,409 $ 1,133,303 The foreign currency translation adjustments resulted from our foreign subsidiaries with functional currencies that are different than our reporting currency. These goodwill amounts are presented net of reductions from historical impairment adjustments. The gross amounts for GSG were $539.6 million and $536.8 million at January 1, 2023 and October 2, 2022, respectively, excluding accumulated impairment of $17.7 million at each date. The gross amounts of goodwill for CIG were $732.9 million and $712.8 million at January 1, 2023 and October 2, 2022, respectively, excluding accumulated impairment of $121.5 million at each date. We perform our annual goodwill impairment review at the beginning of our fiscal fourth quarter. Our most recent annual review at July 4, 2022 (i.e. the first day of our fourth quarter in fiscal 2022) indicated that we had no impairment of goodwill, and all of our reporting units had estimated fair values that were in excess of their carrying values, including goodwill. At July 4, 2022, and after the reallocation of goodwill on the first day of fiscal 2022, we had no reporting units that had estimated fair values that exceeded their carrying values by less than 165%. We also regularly evaluate whether events and circumstances have occurred that may indicate a potential change in the recoverability of goodwill. We perform interim goodwill impairment reviews between our annual reviews if certain events and circumstances have occurred, such as a deterioration in general economic conditions; an increase in the competitive environment; a change in management, key personnel, strategy or customers; negative or declining cash flows; or a decline in actual or planned revenue or earnings compared with actual and projected results of relevant prior periods. Although we believe that our estimates of fair value for these reporting units are reasonable, if financial performance for these reporting units falls significantly below our expectations or market prices for similar business decline, the goodwill for these reporting units could become impaired. The following table presents the gross amount and accumulated amortization of our acquired identifiable intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets ($ in thousands): Period Ended January 1, 2023 October 2, 2022 Weighted- Gross Accumulated Net Amount Gross Accumulated Net Amount Client relations 5.4 $ 43,601 $ (23,081) $ 20,520 $ 41,676 $ (21,092) $ 20,584 Backlog 0.4 34,837 (33,033) 1,804 33,286 (29,990) 3,296 Trade names 3.5 13,656 (8,444) 5,212 12,711 (7,428) 5,283 Total $ 92,094 $ (64,558) $ 27,536 $ 87,673 $ (58,510) $ 29,163 Amortization expense for the three months e nded January 1, 2023 wa s $3.4 million, compared to $2.7 million for the prior-year period. Estimated amortization expense for the remainder of fiscal 2023 and succeeding years is as follows (in thousands): Amount 2023 (remaining) $ 6,755 2024 5,552 2025 4,719 2026 3,869 2027 2,349 Beyond 4,292 Total $ 27,536

Property and Equipment

Property and Equipment	3 Months Ended
	Jan. 01, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consisted of the following (in thousands): Balance at January 1, October 2, Equipment, furniture and fixtures $ 101,002 $ 96,710 Leasehold improvements 32,985 32,428 Total property and equipment 133,987 129,138 Accumulated depreciation (99,097) (96,822) Property and equipment, net $ 34,890 $ 32,316 The depreciation expense related to property and equipment was $3.2 million for th e three months ended January 1, 2023, compared t o $3.4 million

Stock Repurchase and Dividends

Stock Repurchase and Dividends	3 Months Ended
	Jan. 01, 2023
Stock Repurchase And Dividends [Abstract]
Stock Repurchase and Dividends	Stock Repurchase and Dividends On October 5, 2021, our Board of Directors authorized a new stock repurchase program under which we could repurchase up to $400 million of our common stock . We did not repurchase any shares of our common stock in the first quarter of fiscal 2023. At January 1, 2023, we had a remaining balance of $347.8 million under our stock repurchase program. The following table presents dividends declared and paid in the first three months of fiscal 2023 and 2022: Declare Date Dividend Paid Per Share Record Date Payment Date Dividend Paid November 7, 2022 $ 0.23 November 21, 2022 December 9, 2022 $ 12,186 November 15, 2021 $ 0.20 December 2, 2021 December 20, 2021 $ 10,793 Subsequent Event. On January 30, 2023, our Board of Directors declared a quarterly cash dividend of $0.23 per share payable on February 24, 2023 to stockholders of record as of the close of business on February 13, 2023.

Leases

Leases	3 Months Ended
	Jan. 01, 2023
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 ten 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 "Right-of-use assets, operating leases", "Short-term lease liabilities, operating leases" and "Long-term lease liabilities, operating leases" in the consolidated balance sheets. Our finance leases are primarily for certain information technology equipment , and are included in "Other non-current assets", "Other current liabilities" and "Other non-current liabilities" in the consolidated balance sheets at January 1, 2023 and October 2, 2022. Right-of-use ("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 (in thousands): Three Months Ended January 1, January 2, Operating lease cost $ 20,961 $ 21,751 Sublease income (32) (125) Total lease cost $ 20,929 $ 21,626 Supplemental cash flow information related to leases is as follows (in thousands): Three Months Ended January 1, January 2, Operating cash flows for operating leases $ 16,493 $ 17,519 Financing cash flows for finance leases 1,316 945 Right-of-use assets obtained in exchange for new operating lease liabilities 11,117 12,347 Right-of-use assets obtained in exchange for new finance lease liabilities $ 1,431 $ 1,349 Supplemental balance sheet and other information related to leases are as follows (in thousands): Balance at January 1, 2023 October 2, 2022 Operating leases: Right-of-use assets $ 182,500 $ 182,319 Lease liabilities: Current 55,809 57,865 Non-current 148,034 146,285 Total operating lease liabilities $ 203,843 $ 204,150 Finance leases: Other non-current assets $ 9,932 $ 9,564 Other current liabilities $ 4,582 $ 4,481 Other non-current liabilities $ 5,343 $ 4,745 Weighted-average remaining lease term: Operating leases 5 years 5 years Finance leases 2 years 2 years Weighted-average discount rate: Operating leases 2.2 % 2.2 % Finance leases 3 % 3 % At January 1, 2023, we have approximately $8 million of operating leases that have not yet commenced. A maturity analysis of the future undiscounted cash flows associated with our lease liabilities at January 1, 2023 is as follows (in thousands): Operating Finance 2023 (remaining) $ 49,216 $ 3,787 2024 51,833 3,699 2025 39,744 2,182 2026 25,234 574 2027 17,870 211 Beyond 32,484 — Total lease payments 216,381 10,453 Less: imputed interest (12,538) (521) Total present value of lease liabilities $ 203,843 $ 9,932
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 ten 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 "Right-of-use assets, operating leases", "Short-term lease liabilities, operating leases" and "Long-term lease liabilities, operating leases" in the consolidated balance sheets. Our finance leases are primarily for certain information technology equipment , and are included in "Other non-current assets", "Other current liabilities" and "Other non-current liabilities" in the consolidated balance sheets at January 1, 2023 and October 2, 2022. Right-of-use ("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 (in thousands): Three Months Ended January 1, January 2, Operating lease cost $ 20,961 $ 21,751 Sublease income (32) (125) Total lease cost $ 20,929 $ 21,626 Supplemental cash flow information related to leases is as follows (in thousands): Three Months Ended January 1, January 2, Operating cash flows for operating leases $ 16,493 $ 17,519 Financing cash flows for finance leases 1,316 945 Right-of-use assets obtained in exchange for new operating lease liabilities 11,117 12,347 Right-of-use assets obtained in exchange for new finance lease liabilities $ 1,431 $ 1,349 Supplemental balance sheet and other information related to leases are as follows (in thousands): Balance at January 1, 2023 October 2, 2022 Operating leases: Right-of-use assets $ 182,500 $ 182,319 Lease liabilities: Current 55,809 57,865 Non-current 148,034 146,285 Total operating lease liabilities $ 203,843 $ 204,150 Finance leases: Other non-current assets $ 9,932 $ 9,564 Other current liabilities $ 4,582 $ 4,481 Other non-current liabilities $ 5,343 $ 4,745 Weighted-average remaining lease term: Operating leases 5 years 5 years Finance leases 2 years 2 years Weighted-average discount rate: Operating leases 2.2 % 2.2 % Finance leases 3 % 3 % At January 1, 2023, we have approximately $8 million of operating leases that have not yet commenced. A maturity analysis of the future undiscounted cash flows associated with our lease liabilities at January 1, 2023 is as follows (in thousands): Operating Finance 2023 (remaining) $ 49,216 $ 3,787 2024 51,833 3,699 2025 39,744 2,182 2026 25,234 574 2027 17,870 211 Beyond 32,484 — Total lease payments 216,381 10,453 Less: imputed interest (12,538) (521) Total present value of lease liabilities $ 203,843 $ 9,932

Stockholders' Equity and Stock

Stockholders' Equity and Stock Compensation Plans	3 Months Ended
	Jan. 01, 2023
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 1, 2023 was $7.2 million, compared to $5.8 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 2023, we awarded 55,708 performance share units (“PSUs”) to our non-employee directors and executive officers at an estimated fair value of $204.00 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 98,305 restricted stock units

Earnings per Share ("EPS")

Earnings per Share ("EPS")	3 Months Ended
	Jan. 01, 2023
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 (in thousands, except per share data): Three Months Ended January 1, January 2, Net income attributable to Tetra Tech $ 116,706 $ 68,489 Weighted-average common shares outstanding – basic 53,069 53,937 Effect of dilutive stock options and unvested restricted stock 460 640 Weighted-average common shares outstanding – diluted 53,529 54,577 Earnings per share attributable to Tetra Tech: Basic $ 2.20 $ 1.27 Diluted $ 2.18 $ 1.25

Income Taxes

Income Taxes	3 Months Ended
	Jan. 01, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective tax rates for the first three months of fiscal 2023 and 2022 were 24.5% and 18.8%, respectively. Income tax expense was reduced by $1.7 million and $4.5 million of excess tax benefits on share-based payments in the first quarters of fiscal 2023 and 2022, respectively. Excluding the impact of the excess tax benefits on share-based payments, our effective tax rates in the first quarters of fiscal 2023 and 2022 were 25.7% an d 24.1%, r espectively. At January 1, 2023 and October 2, 2022, the liability for income taxes associated with uncertain tax positions was $10.8 million and $10.6 million, respectively. These uncertain tax positions substantially relate to ongoing examinations. It is reasonably p ossible that these liabilities may decrease within the next 12 months as certain examinations are resolved. 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. 01, 2023
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. 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. based federal and municipal clients, especially in water infrastructure, flood protection and solid waste. 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 inclusive of the 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. 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 (in thousands): Three Months Ended January 1, January 2, Revenue GSG $ 471,067 $ 456,099 CIG 439,556 416,286 Elimination of inter-segment revenue (15,857) (13,875) Total revenue $ 894,766 $ 858,510 Income from operations GSG $ 60,347 $ 51,179 CIG 50,108 45,308 Corporate (1) (18,405) (9,267) Total income from operations $ 92,050 $ 87,220 (1) Includes amortization of intangibles, other costs and other income not allocable to our reportable segments. Balance at January 1, October 2, Total Assets GSG $ 586,128 $ 558,764 CIG 742,288 688,640 Corporate (1) 1,403,064 1,375,372 Total assets $ 2,731,480 $ 2,622,776 (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. 01, 2023
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 2, 2022 ). The carrying value of our long-term debt approximated fair value at January 1, 2023 and October 2, 2022. At January 1, 2023, we had bor rowing s of $240.6 million outstanding under our Amended Credit Agreement, which were used to fund business acquisitions, work ing capital needs, stock repurchases, dividends, capital expenditures and contingent earn-outs.

Credit Facility

Credit Facility	3 Months Ended
	Jan. 01, 2023
Debt Disclosure [Abstract]
Credit Facility	Credit Facility On October 26, 2022, we entered into a Third Amended and Restated Credit Agreement that provides for an additional $500 million senior secured term loan facility (the "New Term Loan Facility") increasing our total borrowing capacity to $1.55 billion. Subsequent Event. On January 23, 2023, we acquired RPS and drew the entire amount of the New Term Loan Facility to partially finance the RPS acquisition. The remaining purchase price was financed with existing cash on hand and borrowings under the existing Amended Revolving Credit Facility. The New Term Loan Facility is not subject to any amortization payments of principal and matures on the third anniversary of the RPS acquisition closing date. On February 18, 2022, we entered into Amendment No. 2 to Second Amended and Restated Credit Agreement (“Amended Credit Agreement”) with a total borrowing capacity of $1.05 billion that will mature in February 2027. The Amended Credit Agreement is a $750 million senior secured, five-year facility that provides for a $250 million term loan facility (the “Amended Term Loan Facility”) and a $500 million revolving credit facility (the “Amended Revolving Credit Facility”). In addition, the Amended Credit Agreement includes a $300 million accordion feature that allows us to increase the Amended Credit Agreement to $1.05 billion subject to lender approval. The Amended Credit Agreement provides for, among other things, (i) refinance indebtedness under our Credit Agreement dated at July 30, 2018; (ii) finance open market repurchases of common stock, acquisitions, and cash dividends and distributions; and (iii) utilize the proceeds for working capital, capital expenditures and other general corporate purposes. The Amended Credit Agreement provides for a reduction in the interest grid for meeting certain sustainability targets related to the (i) reduction of greenhouse gas emissions through the Company’s projects and operational sustainability initiatives and (ii) improvement of peoples’ lives as a result of the Company’s projects that provide environmental, social and governance benefits. The Amended Revolving Credit Facility includes a $100 million sublimit for the issuance of standby letters of credit, a $20 million sublimit for swingline loans, and a $300 million sublimit for multicurrency borrowings and letters of credit. The entire Amended Term Loan Facility was drawn on February 18, 2022. The Amended Term Loan Facility is subject to quarterly amortization of principal at 5% annually commencing June 30, 2022. We may borrow on the Amended Revolving Credit Facility, at our option, at either (a) a benchmark rate plus a margin that ranges from 1.000% to 1.875% per annum, or (b) a base rate for loans in U.S. dollars (the highest of the U.S. federal funds rate plus 0.50% per annum, the bank’s prime rate or the Secured Overnight Financing Rate ("SOFR") rate plus 1.00%, plus a margin that ranges from 0% to 0.875% per annum. In each case, the applicable margin is based on our Consolidated Leverage Ratio, calculated quarterly. The Amended Term Loan Facility is subject to the same interest rate provisions. The Amended Credit Agreement expires on February 18, 2027, or earlier at our discretion upon payment in full of loans and other obligations. The Amended Credit Agreement contains certain affirmative and restrictive covenants, and customary events of default. The financial covenants provide for a maximum Consolidated Leverage Ratio of 3.25 to 1.00 (total funded debt/EBITDA, as defined in the Amended Credit Agreement) and a minimum Consolidated Interest Coverage Ratio of 3.00 to 1.00 (EBITDA/Consolidated Interest Charges, as defined in the Amended Credit Agreement). Our obligations under the Amended Credit Agreement are guaranteed by certain of our domestic subsidiaries and are secured by first priority liens on (i) the equity interests of certain of our subsidiaries, including those subsidiaries that are guarantors or borrowers under the Amended Credit Agreement, and (ii) the accounts receivable, general intangibles and intercompany loans, and those of our subsidiaries that are guarantors or borrowers.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Jan. 01, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We use certain interest rate derivative contracts to hedge interest rate exposures on our variable rate debt. We also enter into 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. Our derivative contracts are categorized within Level 2 of the fair value hierarchy. We entered into a forward contract in the fourth quarter of fiscal 2022 to acquire GBP 714.0 million at a rate of 1.0852 for a total of USD 774.8 million that was integrated with our planned acquisition of RPS. This contract matured on December 30, 2022. On December 28, 2022, we entered into an extension of the integrated forward contr act to acquire GBP 714.0 million at a rate of 1.086 for a total of USD 775.4 million, extending the maturity date to January 23, 2023, the closing date of the RPS acquisition. Although an effective economic hedge of our foreign exchange risk related to this transaction, the forward contract does not qualify for hedge accounting. As a result, the forward contract is marked-to-market with changes in fair value recogni zed in earnings each period. The intrinsic value of the forward contract was immaterial at inception as the GBP/USD spot and forward exchange rates were essentially the same. The fair value of the forward contract at October 2, 2022 was $19.9 million, and an unrealized gain of the same amount was recognized in the fourth quarter of fiscal 2022 results. The fair value of the forward contract at January 1, 2023 was $87.9 million, which is reported in the "Prepaid expenses and other current assets" on our consolidated balance sheet at January 1, 2023. This resulted in an unrealized gain of $68.0 million in the first quarter of fiscal 2023, which was recognized in earnings and reported in the “Other non-operating income" on our consolidated income statement. The forward contract was settled on January 23, 2023, with a cumulative gain of approximately $109 million. 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. At January 1, 2023, the notional principal of our outstanding interest swap agreements was $196.9 million ($39.4 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 1, 2023 and October 2, 2022, the fair values of the effective portion of our interest rate swap agreements designated as cash flow hedges before tax effect were unrealized gains of $2.3 million and $2.4 million, respectively, which were reported in "Other non-current assets" on our consolidated balance sheets. Additionally, the related loss of $0.1 million for the three months ended January 1, 2023, compared to the related gain of $2.7 million for the prior-year period, were recognized and reported on our consolidated statements of comprehensive income. We expect to reclassify a credit of $2.2 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 quarter of fiscal 2023.

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income	3 Months Ended
	Jan. 01, 2023
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 1, 2023 and January 2, 2022 related to reclassifications out of accumulated other comprehensive income are summarized as follows (in thousands): Three Months Ended Foreign Gain (Loss) Accumulated Other Comprehensive Income (Loss) 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) Balance at October 2, 2022 $ (210,556) $ 2,412 $ (208,144) Other comprehensive income (loss) before reclassifications 33,107 (535) 32,572 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — 446 446 Net current-period other comprehensive income (loss) 33,107 (89) 33,018 Balance at January 1, 2023 $ (177,449) $ 2,323 $ (175,126) (1) This accumulated other comprehensive component is reclassified to “Interest expense” in our consolidated statements of income. See Note 15 “Derivative Financial Instruments”, for more information.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Jan. 01, 2023
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 of contract related to TtEC's contracts to perform environmental remediation services at the former Hunters Point Naval Shipyard in San Francisco, California. TtEC disputes the claims and will defend this matter vigorously. We are currently unable to determine the probability of the outcome of this matter or the range of reasonably possible loss, if any.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Jan. 01, 2023
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 th e first quarters o f fiscal 2023 and 2022 was approxim ately $23 million and $26 million, respectively. Our related reimbursable costs for the first quarters of fiscal 2023 and 2022 were approximately $22 million and $25 million, respectively. Our consolidated balance sheets also included the following amounts related to these services (in thousands): Balance at January 1, October 2, 2022 Accounts receivable, net $ 18,376 $ 16,818 Contract assets 2,140 2,935 Contract liabilities 3,514 3,464

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Jan. 01, 2023
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	In November 2021, the Financial Accounting Standards Board ("FASB") issued ASU 2021-10, Government Assistance (Topic 832), which requires annual 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 was effective for us beginning in the first quarter of fiscal 2023. In fiscal 2020, the Canadian federal government implemented the Canadian Emergency Wage Subsidy ("CEWS") program in response to the negative impact of the coronavirus disease 2019 (" COVID-19") pandemic on businesses operating in Canada. Our Canadian legal entities qualified for and applied for these CEWS cash benefits to partially offset the impacts of revenue reductions and on-going staffing costs. The $26.0 million total received was initially recorded in "Other current liabilities" until all potential amendments to the qualification criteria, including some that were proposed with retroactive application, were finalized in fiscal 2022. As there are no further contingencies, beginning in fiscal 2023, the amounts received will be distributed to all Canadian employees. We expect to distribute approximately $9 million in the next twelve months. Accordingly, this amount was reclassified from "Other current liabilities" to "Accrued compensation" on our consolidated balance sheet at October 2, 2022. The remaining $17.0 million, which we expect to distribute beyond one year, was reclassified to "Other non-current liabilities". We do not expect there will be any related impact to our operating income, and we have no outstanding applications for further government assistance.
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 $3.8 billion of RUPO at January 1, 2023. 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 1, 2023 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.

Revenue and Contract Balances (

Revenue and Contract Balances (Tables)	3 Months Ended
	Jan. 01, 2023
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 (in thousands): Three Months Ended January 1, January 2, Client Sector: U.S. federal government (1) $ 276,075 $ 266,797 U.S. state and local government 153,195 159,008 U.S. commercial 198,956 176,904 International (2) 266,540 255,801 Total $ 894,766 $ 858,510 Contract Type: Fixed-price $ 327,737 $ 331,248 Time-and-materials 420,570 395,648 Cost-plus 146,459 131,614 Total $ 894,766 $ 858,510 (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 (in thousands): Balance at January 1, October 2, 2022 Contract assets (1) $ 80,903 $ 92,405 Contract liabilities 274,118 241,340 Net contract liabilities $ (193,215) $ (148,935) (1) Inclu
Components of net accounts receivable	Net accounts receivable consisted of the following (in thousands): Balance at January 1, October 2, Billed $ 486,027 $ 491,700 Unbilled 313,782 267,161 Total accounts receivable 799,809 758,861 Allowance for doubtful accounts (3,937) (3,749) Total accounts receivable, net $ 795,872 $ 755,112
Remaining performance obligation, expected timing	We expect to satisfy our RUPO at January 1, 2023 over the following periods (in thousands): Amount Within 12 months $ 2,460,171 Beyond 1,329,949 Total $ 3,790,120

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Jan. 01, 2023
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 (in thousands): GSG CIG Total Balance at October 2, 2022 $ 519,102 $ 591,310 $ 1,110,412 Translation adjustments 2,792 20,099 22,891 Balance at January 1, 2023 $ 521,894 $ 611,409 $ 1,133,303
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 ($ in thousands): Period Ended January 1, 2023 October 2, 2022 Weighted- Gross Accumulated Net Amount Gross Accumulated Net Amount Client relations 5.4 $ 43,601 $ (23,081) $ 20,520 $ 41,676 $ (21,092) $ 20,584 Backlog 0.4 34,837 (33,033) 1,804 33,286 (29,990) 3,296 Trade names 3.5 13,656 (8,444) 5,212 12,711 (7,428) 5,283 Total $ 92,094 $ (64,558) $ 27,536 $ 87,673 $ (58,510) $ 29,163
Estimated amortization expense for the remainder of the fiscal year and the succeeding years	Estimated amortization expense for the remainder of fiscal 2023 and succeeding years is as follows (in thousands): Amount 2023 (remaining) $ 6,755 2024 5,552 2025 4,719 2026 3,869 2027 2,349 Beyond 4,292 Total $ 27,536

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Jan. 01, 2023
Property, Plant and Equipment [Abstract]
Schedule of components of property and equipment	Property and equipment consisted of the following (in thousands): Balance at January 1, October 2, Equipment, furniture and fixtures $ 101,002 $ 96,710 Leasehold improvements 32,985 32,428 Total property and equipment 133,987 129,138 Accumulated depreciation (99,097) (96,822) Property and equipment, net $ 34,890 $ 32,316

Stock Repurchase and Dividends

Stock Repurchase and Dividends (Tables)	3 Months Ended
	Jan. 01, 2023
Stock Repurchase And Dividends [Abstract]
Summary of dividends declared and paid	The following table presents dividends declared and paid in the first three months of fiscal 2023 and 2022: Declare Date Dividend Paid Per Share Record Date Payment Date Dividend Paid November 7, 2022 $ 0.23 November 21, 2022 December 9, 2022 $ 12,186 November 15, 2021 $ 0.20 December 2, 2021 December 20, 2021 $ 10,793

Leases (Tables)

Leases (Tables)	3 Months Ended
	Jan. 01, 2023
Leases [Abstract]
Summary of components of lease cost	The components of lease costs are as follows (in thousands): Three Months Ended January 1, January 2, Operating lease cost $ 20,961 $ 21,751 Sublease income (32) (125) Total lease cost $ 20,929 $ 21,626 Supplemental cash flow information related to leases is as follows (in thousands): Three Months Ended January 1, January 2, Operating cash flows for operating leases $ 16,493 $ 17,519 Financing cash flows for finance leases 1,316 945 Right-of-use assets obtained in exchange for new operating lease liabilities 11,117 12,347 Right-of-use assets obtained in exchange for new finance lease liabilities $ 1,431 $ 1,349
Summary of supplemental balance sheet and other information	Supplemental balance sheet and other information related to leases are as follows (in thousands): Balance at January 1, 2023 October 2, 2022 Operating leases: Right-of-use assets $ 182,500 $ 182,319 Lease liabilities: Current 55,809 57,865 Non-current 148,034 146,285 Total operating lease liabilities $ 203,843 $ 204,150 Finance leases: Other non-current assets $ 9,932 $ 9,564 Other current liabilities $ 4,582 $ 4,481 Other non-current liabilities $ 5,343 $ 4,745 Weighted-average remaining lease term: Operating leases 5 years 5 years Finance leases 2 years 2 years Weighted-average discount rate: Operating leases 2.2 % 2.2 % Finance leases 3 % 3 %
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 lease liabilities at January 1, 2023 is as follows (in thousands): Operating Finance 2023 (remaining) $ 49,216 $ 3,787 2024 51,833 3,699 2025 39,744 2,182 2026 25,234 574 2027 17,870 211 Beyond 32,484 — Total lease payments 216,381 10,453 Less: imputed interest (12,538) (521) Total present value of lease liabilities $ 203,843 $ 9,932

Earnings per Share ("EPS") (Tab

Earnings per Share ("EPS") (Tables)	3 Months Ended
	Jan. 01, 2023
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 (in thousands, except per share data): Three Months Ended January 1, January 2, Net income attributable to Tetra Tech $ 116,706 $ 68,489 Weighted-average common shares outstanding – basic 53,069 53,937 Effect of dilutive stock options and unvested restricted stock 460 640 Weighted-average common shares outstanding – diluted 53,529 54,577 Earnings per share attributable to Tetra Tech: Basic $ 2.20 $ 1.27 Diluted $ 2.18 $ 1.25

Reportable Segments (Tables)

Reportable Segments (Tables)	3 Months Ended
	Jan. 01, 2023
Segment Reporting [Abstract]
Summarized financial information of reportable segments	The following tables summarize financial information regarding our reportable segments (in thousands): Three Months Ended January 1, January 2, Revenue GSG $ 471,067 $ 456,099 CIG 439,556 416,286 Elimination of inter-segment revenue (15,857) (13,875) Total revenue $ 894,766 $ 858,510 Income from operations GSG $ 60,347 $ 51,179 CIG 50,108 45,308 Corporate (1) (18,405) (9,267) Total income from operations $ 92,050 $ 87,220 (1) Includes amortization of intangibles, other costs and other income not allocable to our reportable segments. Balance at January 1, October 2, Total Assets GSG $ 586,128 $ 558,764 CIG 742,288 688,640 Corporate (1) 1,403,064 1,375,372 Total assets $ 2,731,480 $ 2,622,776 (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. 01, 2023
Equity [Abstract]
Summary of reclassifications out of accumulated other comprehensive income	The accumulated balances and activities for the three months ended January 1, 2023 and January 2, 2022 related to reclassifications out of accumulated other comprehensive income are summarized as follows (in thousands): Three Months Ended Foreign Gain (Loss) Accumulated Other Comprehensive Income (Loss) 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) Balance at October 2, 2022 $ (210,556) $ 2,412 $ (208,144) Other comprehensive income (loss) before reclassifications 33,107 (535) 32,572 Amounts reclassified from accumulated other comprehensive loss Interest rate contracts, net of tax (1) — 446 446 Net current-period other comprehensive income (loss) 33,107 (89) 33,018 Balance at January 1, 2023 $ (177,449) $ 2,323 $ (175,126) (1) This accumulated other comprehensive component is reclassified to “Interest expense” in our consolidated statements of income. See Note 15 “Derivative Financial Instruments”, for more information.

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Jan. 01, 2023
Related Party Transactions [Abstract]
Schedule of related party transactions	Our consolidated balance sheets also included the following amounts related to these services (in thousands): Balance at January 1, October 2, 2022 Accounts receivable, net $ 18,376 $ 16,818 Contract assets 2,140 2,935 Contract liabilities 3,514 3,464

Recent Accounting Pronounceme_3

Recent Accounting Pronouncements (Details) $ in Millions	Oct. 02, 2022 USD ($)
Accounting Changes and Error Corrections [Abstract]
Government assistance, amount, cumulative, current	$ 26
Government assistance, amount expected to be recognized in next twelve months	9
Government assistance, amount, cumulative, noncurrent	$ 17

Revenue and Contract Balances -

Revenue and Contract Balances - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 894,766	$ 858,510
Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	327,737	331,248
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue	420,570	395,648
Cost-plus
Disaggregation of Revenue [Line Items]
Revenue	146,459	131,614
U.S. federal government
Disaggregation of Revenue [Line Items]
Revenue	276,075	266,797
U.S. state and local government
Disaggregation of Revenue [Line Items]
Revenue	153,195	159,008
U.S. commercial
Disaggregation of Revenue [Line Items]
Revenue	198,956	176,904
International
Disaggregation of Revenue [Line Items]
Revenue	$ 266,540	$ 255,801

Revenue and Contract Balances_2

Revenue and Contract Balances - Summary of Contract Liabilities/Assets (Details) - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Disaggregation of Revenue [Line Items]
Contract assets	$ 80,903	$ 92,405
Contract liabilities	274,118	241,340
Net contract liabilities	(193,215)	(148,935)
Contract Retentions
Disaggregation of Revenue [Line Items]
Contract assets	$ 17,200	$ 23,300

Revenue and Contract Balances_3

Revenue and Contract Balances - Narrative (Details) - USD ($)	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022	Oct. 02, 2022
Disaggregation of Revenue [Line Items]
Contract liability revenue recognized during the period	$ 81,000,000	$ 63,000,000
Net favorable (unfavorable) revenue and operating income adjustments	3,500,000	2,800,000
Liabilities for anticipated losses	7,600,000		$ 10,000,000
Estimated cost to complete the related contracts	$ 55,000,000		80,000,000
Period for billing and collecting unbilled receivables	12 months
Remaining unsatisfied performance obligation	$ 3,790,120,000
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
Remediation and Construction Management
Disaggregation of Revenue [Line Items]
Accounts receivable related to claims and requests for equitable adjustment on contracts			$ 0
CIG
Disaggregation of Revenue [Line Items]
Net favorable (unfavorable) revenue and operating income adjustments	$ 0	$ 0

Revenue and Contract Balances_4

Revenue and Contract Balances - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Revenue from Contract with Customer [Abstract]
Billed	$ 486,027	$ 491,700
Unbilled	313,782	267,161
Total accounts receivable	799,809	758,861
Allowance for doubtful accounts	(3,937)	(3,749)
Total accounts receivable, net	$ 795,872	$ 755,112

Revenue and Contract Balances_5

Revenue and Contract Balances - Remaining Unsatisfied Performance Obligations (Details) $ in Thousands	Jan. 01, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining unsatisfied performance obligation	$ 3,790,120
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	$ 2,460,171
Remaining unsatisfied performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining unsatisfied performance obligation	$ 1,329,949
Remaining unsatisfied performance obligation, expected timing of satisfaction

Acquisitions (Details)

Acquisitions (Details) £ / shares in Units, £ in Millions, $ in Millions			3 Months Ended	12 Months Ended
	Jan. 03, 2023 employee program	Sep. 23, 2022 employee £ / shares	Jan. 01, 2023 USD ($)	Oct. 02, 2022 USD ($) acquisition	Jan. 23, 2023 GBP (£)	Dec. 31, 2022 GBP (£)	Dec. 30, 2022 USD ($)	Dec. 28, 2022 GBP (£)	Dec. 28, 2022 USD ($)
Business Acquisition [Line Items]
Pence per share expected to be acquired | £ / shares		£ 2.22
Number of acquisitions | acquisition				4
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
RPS Group PLC
Business Acquisition [Line Items]
Number of employees | employee		5,000
RPS Group PLC | Foreign Exchange Forward
Business Acquisition [Line Items]
Notional amount						£ 714	$ 774.8	£ 714	$ 775.4
RPS Group PLC | Subsequent Event | Foreign Exchange Forward
Business Acquisition [Line Items]
Notional amount | £					£ 714
Amyx, Inc. | Subsequent Event
Business Acquisition [Line Items]
Number of employees | employee	500
Number of government programs acquired | program	30
Business acquisitions
Business Acquisition [Line Items]
Fair value of acquisition purchase price				$ 88.3
Aggregate maximum of contingent consideration				47
Initial cash payments				44
Receivables related to estimated post-closing adjustments				2.5
Payables related to promissory note				15.5
Contingent earn-out liability				$ 31.3
Business acquisitions | Minimum
Business Acquisition [Line Items]
Earn-out period				3 years
Business acquisitions | Maximum
Business Acquisition [Line Items]
Earn-out period				5 years
All acquisitions
Business Acquisition [Line Items]
Aggregate maximum of contingent consideration			$ 120.9
Contingent earn-out liability			$ 69

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended
	Jan. 01, 2023 USD ($)
Goodwill
Balance at beginning of the period	$ 1,110,412
Translation adjustments	22,891
Balance at end of the period	1,133,303
GSG
Goodwill
Balance at beginning of the period	519,102
Translation adjustments	2,792
Balance at end of the period	521,894
CIG
Goodwill
Balance at beginning of the period	591,310
Translation adjustments	20,099
Balance at end of the period	$ 611,409

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)		3 Months Ended
	Jul. 04, 2022	Jan. 01, 2023	Jan. 02, 2022	Oct. 02, 2022
Goodwill [Line Items]
Impairment of goodwill	$ 0
Percentage of excess of fair value over carrying value (less than)	165%
Amortization expense		$ 3,400,000	$ 2,700,000
GSG
Goodwill [Line Items]
Gross amounts of goodwill		539,600,000		$ 536,800,000
Accumulated impairment		17,700,000		17,700,000
CIG
Goodwill [Line Items]
Gross amounts of goodwill		732,900,000		712,800,000
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. 01, 2023	Oct. 02, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 92,094	$ 87,673
Accumulated Amortization	(64,558)	(58,510)
Net Amount	$ 27,536	29,163
Client relations
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	5 years 4 months 24 days
Gross Amount	$ 43,601	41,676
Accumulated Amortization	(23,081)	(21,092)
Net Amount	$ 20,520	20,584
Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	4 months 24 days
Gross Amount	$ 34,837	33,286
Accumulated Amortization	(33,033)	(29,990)
Net Amount	$ 1,804	3,296
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	3 years 6 months
Gross Amount	$ 13,656	12,711
Accumulated Amortization	(8,444)	(7,428)
Net Amount	$ 5,212	$ 5,283

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
2023 (remaining)	$ 6,755
2024	5,552
2025	4,719
2026	3,869
2027	2,349
Beyond	4,292
Net Amount	$ 27,536	$ 29,163

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022	Oct. 02, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 133,987		$ 129,138
Accumulated depreciation	(99,097)		(96,822)
Property and equipment, net	34,890		32,316
Depreciation expense related to property and equipment	3,200	$ 3,400
Equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	101,002		96,710
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 32,985		$ 32,428

Stock Repurchase and Dividend_2

Stock Repurchase and Dividends - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended
	Feb. 24, 2023	Jan. 30, 2023	Dec. 09, 2022	Dec. 20, 2021	Jan. 01, 2023	Jan. 02, 2022	Oct. 05, 2021
Subsequent Event [Line Items]
Remaining authorized amount under share repurchase program					$ 347.8
Dividend paid per share (in dollars per share)			$ 0.23	$ 0.20	$ 0.23	$ 0.20
Subsequent Event
Subsequent Event [Line Items]
Quarterly cash dividend declared (in dollars per share)		$ 0.23
Forecast
Subsequent Event [Line Items]
Dividend paid per share (in dollars per share)	$ 0.23
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			3 Months Ended
	Dec. 09, 2022	Dec. 20, 2021	Jan. 01, 2023	Jan. 02, 2022
Stock Repurchase And Dividends [Abstract]
Dividend paid per share (in dollars per share)	$ 0.23	$ 0.20	$ 0.23	$ 0.20
Dividend Paid	$ 12,186	$ 10,793

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Lessee, Lease, Description [Line Items]
Renewal term (up to)	5 years
Other non-current assets	$ 9,932	$ 9,564
Total present value of lease liabilities	9,932
Operating leases not yet commenced	$ 8,000
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 month
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	10 years

Leases - Components of Lease Co

Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Leases [Abstract]
Operating lease cost	$ 20,961	$ 21,751
Sublease income	(32)	(125)
Total lease cost	$ 20,929	$ 21,626

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Leases [Abstract]
Operating cash flows for operating leases	$ 16,493	$ 17,519
Financing cash flows for finance leases	1,316	945
Right-of-use assets obtained in exchange for new operating lease liabilities	11,117	12,347
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 1,431	$ 1,349

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet and Other Information (Details) - USD ($) $ in Thousands	Jan. 01, 2023	Oct. 02, 2022
Operating leases:
Right-of-use assets	$ 182,500	$ 182,319
Lease liabilities:
Current	55,809	57,865
Non-current	148,034	146,285
Total operating lease liabilities	203,843	204,150
Finance leases:
Other non-current assets	9,932	9,564
Other current liabilities	4,582	4,481
Other non-current liabilities	$ 5,343	$ 4,745
Weighted-average remaining lease term:
Operating leases	5 years	5 years
Finance leases	2 years	2 years
Weighted-average discount rate:
Operating leases	2.20%	2.20%
Finance leases	3%	3%

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. 01, 2023	Oct. 02, 2022
Operating Leases
2023 (remaining)	$ 49,216
2024	51,833
2025	39,744
2026	25,234
2027	17,870
Beyond	32,484
Total lease payments	216,381
Less: imputed interest	(12,538)
Total present value of lease liabilities	203,843	$ 204,150
Finance Leases
2023 (remaining)	3,787
2024	3,699
2025	2,182
2026	574
2027	211
Beyond	0
Total lease payments	10,453
Less: imputed interest	(521)
Total present value of lease liabilities	$ 9,932

Stockholders' Equity and Stoc_2

Stockholders' Equity and Stock Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 7.2	$ 5.8
PSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	55,708
Fair value of awards granted (in dollars per share)	$ 204
Vesting period	3 years
Percentage of shares that ultimately vest depending on growth in diluted earnings per share	50%
Percentage of shares that ultimately vest depending on the shareholder return relative to peer group of companies over vesting period	50%
RSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	98,305
Fair value of awards granted (in dollars per share)	$ 156.52
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. 01, 2023	Jan. 02, 2022
Earnings Per Share [Abstract]
Net income attributable to Tetra Tech, basic	$ 116,706	$ 68,489
Net income attributable to Tetra Tech, diluted	$ 116,706	$ 68,489
Weighted-average common shares outstanding – basic (in shares)	53,069	53,937
Effect of dilutive stock options and unvested restricted stock (in shares)	460	640
Weighted-average common stock outstanding – diluted (in shares)	53,529	54,577
Earnings per share attributable to Tetra Tech:
Basic (in dollars per share)	$ 2.20	$ 1.27
Diluted (in dollars per share)	$ 2.18	$ 1.25

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022	Oct. 02, 2022
Income Tax Disclosure [Abstract]
Effective tax rate	24.50%	18.80%
Reduction in income tax expense due to excess tax benefits on share-based payments	$ 1.7	$ 4.5
Effective tax rate, excluding excess tax benefits on share-based payments	25.70%	24.10%
Liability for uncertain tax positions	$ 10.8		$ 10.6

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended
	Jan. 01, 2023 USD ($) segment	Jan. 02, 2022 USD ($)	Oct. 02, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Revenue	$ 894,766	$ 858,510
Income from operations	92,050	87,220
Total Assets	2,731,480		$ 2,622,776
Operating segments | GSG
Segment Reporting Information [Line Items]
Revenue	471,067	456,099
Income from operations	60,347	51,179
Total Assets	586,128		558,764
Operating segments | CIG
Segment Reporting Information [Line Items]
Revenue	439,556	416,286
Income from operations	50,108	45,308
Total Assets	742,288		688,640
Elimination of inter-segment revenue
Segment Reporting Information [Line Items]
Revenue	(15,857)	(13,875)
Corporate
Segment Reporting Information [Line Items]
Income from operations	(18,405)	$ (9,267)
Total Assets	$ 1,403,064		$ 1,375,372

Fair Value Measurements (Detail

Fair Value Measurements (Details) $ in Millions	Jan. 01, 2023 USD ($)
Amended Credit Agreement
Debt Instrument [Line Items]
Amount outstanding under credit facility	$ 240.6

Credit Facility (Details)

Credit Facility (Details) - Amended Credit Agreement - USD ($)	Feb. 18, 2022	Oct. 26, 2022
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 750,000,000
Accordion feature, higher borrowing capacity option	$ 1,050,000,000	$ 1,550,000,000
Debt instrument term	5 years
Accordion feature, increase limit	$ 300,000,000
Annual principal payment, amortization percentage	5%
Debt covenant, maximum consolidated leverage ratio	3.25
Debt covenant, maximum consolidated leverage ratio	3
New Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 500,000,000
Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 250,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 500,000,000
Revolving Credit Facility | Base Rate | Fed Funds Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Revolving Credit Facility | Base Rate | Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1%
Revolving Credit Facility | Minimum | Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1%
Revolving Credit Facility | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0%
Revolving Credit Facility | Maximum | Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.875%
Revolving Credit Facility | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
Standby Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 100,000,000
Swingline Loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity	20,000,000
Multicurrency Borrowings and Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 300,000,000

Derivative Financial Instrume_2

Derivative Financial Instruments (Details) $ in Thousands, £ in Millions		3 Months Ended		12 Months Ended
	Jan. 23, 2023 USD ($)	Jan. 01, 2023 USD ($)	Jan. 02, 2022 USD ($)	Sep. 30, 2018 agreement	Jan. 23, 2023 GBP (£)	Dec. 31, 2022 GBP (£)	Dec. 30, 2022 USD ($)	Dec. 28, 2022 USD ($)	Dec. 28, 2022 GBP (£)	Oct. 02, 2022 USD ($)
Derivative [Line Items]
Gain on foreign currency forward contract		$ 67,995	$ 0
Gains (losses) on cash flow hedges recognized in comprehensive income		(89)	$ 2,666
RPS Group PLC
Derivative [Line Items]
Derivative, forward exchange rate							1.0852	1.086	1.086
Interest Rate Swap | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		$ 196,900
Number of derivative agreements | agreement				5
Fixed rate		2.79%
Credit to be reclassified during next twelve months		$ 2,200
Interest Rate Swap | Designated as cash flow hedges | Derivatives designated as hedging instruments | Other current liabilities
Derivative [Line Items]
Fair value loss of interest rate swap agreements										$ 2,400
Interest Rate Swap | Designated as cash flow hedges | Derivatives designated as hedging instruments | Other Noncurrent Assets
Derivative [Line Items]
Fair value gain of interest rate swap agreements		2,300
Interest Rate Swap 1 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		39,400
Interest Rate Swap 2 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		39,400
Interest Rate Swap 3 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		39,400
Interest Rate Swap 4 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		39,400
Interest Rate Swap 5 | Designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount		39,400
Foreign Exchange Forward | RPS Group PLC
Derivative [Line Items]
Notional amount						£ 714	$ 774,800	$ 775,400	£ 714
Foreign currency forward contract, asset fair value		87,900								$ 19,900
Gain on foreign currency forward contract		$ 68,000
Foreign Exchange Forward | RPS Group PLC | Subsequent Event
Derivative [Line Items]
Notional amount | £					£ 714
Gain on foreign currency forward contract	$ 109,000

Reclassifications Out of Accu_3

Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2023	Jan. 02, 2022
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	$ 1,183,137	$ 1,234,291
Amounts reclassified from accumulated other comprehensive loss
Other comprehensive income, net of tax	33,018	1,980
Ending balance	1,323,967	1,237,945
Accumulated Other Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	(208,144)	(125,028)
Other comprehensive income (loss) before reclassifications	32,572	3,346
Amounts reclassified from accumulated other comprehensive loss
Interest rate contracts, net of tax	446	(1,366)
Other comprehensive income, net of tax	33,018	1,980
Ending balance	(175,126)	(123,048)
Foreign Currency Translation Adjustments
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	(210,556)	(115,634)
Other comprehensive income (loss) before reclassifications	33,107	(686)
Amounts reclassified from accumulated other comprehensive loss
Other comprehensive income, net of tax	33,107	(686)
Ending balance	(177,449)	(116,320)
Gain (Loss) on Derivative Instruments
Reclassifications out of accumulated other comprehensive income (loss)
Beginning balance	2,412	(9,394)
Other comprehensive income (loss) before reclassifications	(535)	4,032
Amounts reclassified from accumulated other comprehensive loss
Interest rate contracts, net of tax	446	(1,366)
Other comprehensive income, net of tax	(89)	2,666
Ending balance	$ 2,323	$ (6,728)

Commitments and Contingencies (

Commitments and Contingencies (Details)	Jul. 15, 2019 action
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. 01, 2023	Jan. 02, 2022	Oct. 02, 2022
Related Party Transactions [Abstract]
Related party revenues	$ 23,000	$ 26,000
Related party expenses	22,000	$ 25,000
Accounts receivable, net	18,376		$ 16,818
Contract assets	2,140		2,935
Contract liabilities	$ 3,514		$ 3,464