v3.26.1
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 Income (Loss)
Retained Earnings
Non-Controlling Interests
Beginning balance (in shares) at Sep. 29, 2024     267,717        
Beginning balance at Sep. 29, 2024 $ 1,830,413 $ 1,830,322 $ 2,677 $ 35,900 $ (78,875) $ 1,870,620 $ 91
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 6,190 6,135       6,135 55
Foreign currency translation adjustments (74,272) (74,272)     (74,272)    
Net pension adjustments (33) (33)     (33)    
Distributions paid in noncontrolling interests (23)           (23)
Cash dividends (30,900) (30,900)       (30,900)  
Stock-based compensation 17,027 17,027   17,027      
Restricted & performance shares released (in shares)     467        
Restricted & performance shares released (13,848) (13,848) $ 5 (13,853)      
Stock options exercised (in shares)     27        
Stock options exercised 171 171   171      
Shares issued for Employee Stock Purchase Plan (in shares)     458        
Shares issued for Employee Stock Purchase Plan 15,307 15,307 $ 4 15,303      
Stock repurchases (in shares)     (5,166)        
Stock repurchases (176,251) (176,251) $ (51) (54,548)   (121,652)  
Ending balance (in shares) at Mar. 30, 2025     263,503        
Ending balance at Mar. 30, 2025 1,573,781 1,573,658 $ 2,635 0 (153,180) 1,724,203 123
Beginning balance (in shares) at Dec. 29, 2024     268,028        
Beginning balance at Dec. 29, 2024 1,692,019 1,691,897 $ 2,680 21,153 (187,754) 1,855,818 122
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 5,412 5,388       5,388 24
Foreign currency translation adjustments 34,574 34,574     34,574    
Net pension adjustments 0            
Distributions paid in noncontrolling interests (23)           (23)
Cash dividends (15,351) (15,351)       (15,351)  
Stock-based compensation 8,885 8,885   8,885      
Restricted & performance shares released (in shares)     35        
Restricted & performance shares released (541) (541)   (541)      
Stock options exercised (in shares)     6        
Stock options exercised 57 57   57      
Stock repurchases (in shares)     (4,566)        
Stock repurchases (151,251) (151,251) $ (45) (29,554)   (121,652)  
Ending balance (in shares) at Mar. 30, 2025     263,503        
Ending balance at Mar. 30, 2025 1,573,781 1,573,658 $ 2,635 0 (153,180) 1,724,203 123
Beginning balance (in shares) at Sep. 28, 2025     261,418        
Beginning balance at Sep. 28, 2025 1,780,164 1,779,785 $ 2,614 0 (95,777) 1,872,948 379
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 199,020 198,651       198,651 369
Foreign currency translation adjustments 1,398 1,398     1,398    
Net pension adjustments (305) (305)     (305)    
Distributions paid in noncontrolling interests (378)           (378)
Cash dividends (33,852) (33,852)       (33,852)  
Stock-based compensation 17,670 17,670   17,670      
Restricted & performance shares released (in shares)     517        
Restricted & performance shares released (12,430) (12,430) $ 5 (12,435)      
Stock options exercised (in shares)     56        
Stock options exercised 458 458 $ 1 457      
Shares issued for Employee Stock Purchase Plan (in shares)     429        
Shares issued for Employee Stock Purchase Plan 12,570 12,570 $ 4 12,566      
Stock repurchases (in shares)     (2,895)        
Stock repurchases (100,566) (100,566) $ (29) (18,258)   (82,279)  
Ending balance (in shares) at Mar. 29, 2026     259,525        
Ending balance at Mar. 29, 2026 1,863,749 1,863,379 $ 2,595 0 (94,684) 1,955,468 370
Beginning balance (in shares) at Dec. 28, 2025     260,799        
Beginning balance at Dec. 28, 2025 1,846,638 1,846,092 $ 2,608 0 (76,356) 1,919,840 546
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 93,798 93,623       93,623 175
Foreign currency translation adjustments (18,328) (18,328)     (18,328)    
Net pension adjustments 0            
Distributions paid in noncontrolling interests (351)           (351)
Cash dividends (16,915) (16,915)       (16,915)  
Stock-based compensation 9,488 9,488   9,488      
Restricted & performance shares released (in shares)     84        
Restricted & performance shares released (566) (566) $ 1 (567)      
Stock options exercised (in shares)     55        
Stock options exercised 448 448 $ 1 447      
Stock repurchases (in shares)     (1,413)        
Stock repurchases (50,463) (50,463) $ (15) (9,368)   (41,080)  
Ending balance (in shares) at Mar. 29, 2026     259,525        
Ending balance at Mar. 29, 2026 $ 1,863,749 $ 1,863,379 $ 2,595 $ 0 $ (94,684) $ 1,955,468 $ 370