Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 30, 2025	Mar. 31, 2024	Mar. 30, 2025	Mar. 31, 2024
Pay vs Performance Disclosure
Net income attributable to Tetra Tech	$ 5,388	$ 76,446	$ 6,135	$ 151,418

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details