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v3.19.3

Quarterly Financial Information - Unaudited (Details) - USD ($) $ / shares in Units, shares in Thousands |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 01, 2019 | Sep. 29, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 30, 2018 | Sep. 30, 2018 | Jul. 01, 2018 | Apr. 01, 2018 | Dec. 31, 2017 | Sep. 29, 2019 | Sep. 30, 2018 | Oct. 01, 2017
Business acquisition |  |  |  |  |  |  |  |  |  |  |  |
Deferred tax benefit from tax reform remeasurement |  |  |  |  |  |  |  |  | $ 14,700,000 |  |  |
Decrease in revenue related to construction settlement |  |  |  |  |  | $ 10,600,000 |  |  |  |  |  |
Loss from construction settlement claim |  |  |  |  |  | 12,500,000 |  |  |  |  |  |
Decrease in deferred tax valuation allowance |  |  |  | $ 23,400,000 |  |  |  |  |  |  |  |
Impairment of goodwill | $ 0 | $ 7,800,000 |  |  |  |  |  |  |  | $ 7,755,000 | $ 0 | $ 0
Severance and other disposition costs |  | 10,900,000 |  |  |  |  |  |  |  |  |  |
Revenue |  | 841,502,000 | $ 825,793,000 | 722,621,000 | $ 717,431,000 | 739,343,000 | $ 764,795,000 | $ 700,262,000 | 759,749,000 |  |  |
Income from operations |  | 20,665,000 | 64,841,000 | 47,545,000 | 55,711,000 | 43,285,000 | 55,496,000 | 42,716,000 | 48,589,000 | 188,762,000 | 190,086,000 | 183,342,000
Net income attributable to Tetra Tech |  | $ 11,527,000 | $ 49,233,000 | $ 55,911,000 | $ 41,997,000 | $ 28,802,000 | $ 33,322,000 | $ 28,725,000 | $ 46,034,000 | $ 158,668,000 | $ 136,883,000 | $ 117,874,000
Earnings per share attributable to Tetra Tech: |  |  |  |  |  |  |  |  |  |  |  |
Basic (in dollars per share) |  | $ 0.21 | $ 0.90 | $ 1.01 | $ 0.76 | $ 0.52 | $ 0.60 | $ 0.51 | $ 0.82 | $ 2.89 | $ 2.46 | $ 2.07
Diluted (in dollars per share) |  | $ 0.21 | $ 0.88 | $ 1.00 | $ 0.75 | $ 0.51 | $ 0.59 | $ 0.51 | $ 0.81 | $ 2.84 | $ 2.42 | $ 2.04
Weighted-average common shares outstanding: |  |  |  |  |  |  |  |  |  |  |  |
Basic (in shares) |  | 54,617 | 54,819 | 55,143 | 55,390 | 55,341 | 55,537 | 55,841 | 55,855 | 54,986 | 55,670 | 56,911
Diluted (in shares) |  | 55,618 | 55,768 | 55,985 | 56,366 | 56,349 | 56,390 | 56,673 | 56,875 | 55,936 | 56,598 | 57,913
Disposed of by Sale | Non-core field services business |  |  |  |  |  |  |  |  |  |  |  |
Business acquisition |  |  |  |  |  |  |  |  |  |  |  |
Loss on disposition of business |  |  |  |  |  |  | $ 3,400,000 |  |  |  | $ 3,400,000 |
WYG plc |  |  |  |  |  |  |  |  |  |  |  |
Business acquisition |  |  |  |  |  |  |  |  |  |  |  |
Acquisition related costs |  | $ 10,400,000 |  |  |  |  |  |  |  |  |  |

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