Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions | Common Stock | Additional Paid In Capital | Accumulated Other Comprehensive Income (Loss) | Retained Earnings | Total |
Balance at the beginning of the period at Dec. 31, 2021 | $ 30.7 | $ 314.1 | $ (30.9) | $ 1,353.5 | $ 1,667.4 |
Balance (in shares) at Dec. 31, 2021 | 41 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 339.2 | 339.2 |
Other comprehensive income (loss), net of tax | | | 0.2 | | 0.2 |
Share-based compensation | | 4.7 | | | 4.7 |
Shares issued, net of shares withheld for employee taxes | $ 0.2 | (19.5) | | | (19.3) |
Shares issued, net of shares withheld for employee taxes (in shares) | 0.2 | | | | |
Shares repurchased | $ (0.5) | (3.1) | | (65) | (68.6) |
Shares repurchased (in shares) | (0.7) | | | | |
Dividends | | | | (12.9) | (12.9) |
Balance at the end of the period at Mar. 31, 2022 | $ 30.4 | 296.2 | (30.7) | 1,614.8 | 1,910.7 |
Balance (in shares) at Mar. 31, 2022 | 40.5 | | | | |
Balance at the beginning of the period at Dec. 31, 2021 | $ 30.7 | 314.1 | (30.9) | 1,353.5 | 1,667.4 |
Balance (in shares) at Dec. 31, 2021 | 41 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | | 985.9 |
Other comprehensive income (loss), net of tax | | | | | (3.2) |
Balance at the end of the period at Sep. 30, 2022 | $ 28.3 | 290.4 | (34.1) | 2,014 | 2,298.6 |
Balance (in shares) at Sep. 30, 2022 | 37.8 | | | | |
Balance at the beginning of the period at Mar. 31, 2022 | $ 30.4 | 296.2 | (30.7) | 1,614.8 | 1,910.7 |
Balance (in shares) at Mar. 31, 2022 | 40.5 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 380.7 | 380.7 |
Other comprehensive income (loss), net of tax | | | (0.8) | | (0.8) |
Share-based compensation | | 5.7 | | | 5.7 |
Shares issued, net of shares withheld for employee taxes | | (0.2) | | | (0.2) |
Shares issued, net of shares withheld for employee taxes (in shares) | 0.1 | | | | |
Shares repurchased | $ (1.2) | (7) | | (129.9) | (138.1) |
Shares repurchased (in shares) | (1.6) | | | | |
Dividends | | | | (24.4) | (24.4) |
Balance at the end of the period at Jun. 30, 2022 | $ 29.2 | 294.7 | (31.5) | 1,841.2 | 2,133.6 |
Balance (in shares) at Jun. 30, 2022 | 39 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 266 | 266 |
Other comprehensive income (loss), net of tax | | | (2.6) | | (2.6) |
Share-based compensation | | 5.1 | | | 5.1 |
Shares repurchased | $ (0.9) | (9.4) | | (77.7) | (88) |
Shares repurchased (in shares) | (1.2) | | | | |
Equity interest in SSAT | | | | (15.5) | (15.5) |
Balance at the end of the period at Sep. 30, 2022 | $ 28.3 | 290.4 | (34.1) | 2,014 | 2,298.6 |
Balance (in shares) at Sep. 30, 2022 | 37.8 | | | | |
Balance at the beginning of the period at Dec. 31, 2022 | $ 27.2 | 290.4 | (6.9) | 1,986.2 | 2,296.9 |
Balance (in shares) at Dec. 31, 2022 | 36.3 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 34 | 34 |
Other comprehensive income (loss), net of tax | | | 0.6 | | 0.6 |
Share-based compensation | | 4.6 | | | 4.6 |
Shares issued, net of shares withheld for employee taxes | $ 0.2 | (12.6) | | | (12.4) |
Shares issued, net of shares withheld for employee taxes (in shares) | 0.3 | | | | |
Shares repurchased | $ (0.5) | (2.7) | | (38.9) | (42.1) |
Shares repurchased (in shares) | (0.7) | | | | |
Dividends | | | | (11.3) | (11.3) |
Balance at the end of the period at Mar. 31, 2023 | $ 26.9 | 279.7 | (6.3) | 1,970 | 2,270.3 |
Balance (in shares) at Mar. 31, 2023 | 35.9 | | | | |
Balance at the beginning of the period at Dec. 31, 2022 | $ 27.2 | 290.4 | (6.9) | 1,986.2 | 2,296.9 |
Balance (in shares) at Dec. 31, 2022 | 36.3 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | | 234.7 |
Other comprehensive income (loss), net of tax | | | | | (2.4) |
Balance at the end of the period at Sep. 30, 2023 | $ 26.2 | 289.1 | (9.3) | 2,084.3 | 2,390.3 |
Balance (in shares) at Sep. 30, 2023 | 34.9 | | | | |
Balance at the beginning of the period at Mar. 31, 2023 | $ 26.9 | 279.7 | (6.3) | 1,970 | 2,270.3 |
Balance (in shares) at Mar. 31, 2023 | 35.9 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 80.8 | 80.8 |
Other comprehensive income (loss), net of tax | | | (1.6) | | (1.6) |
Share-based compensation | | 5.2 | | | 5.2 |
Shares issued, net of shares withheld for employee taxes | | 0.1 | | | 0.1 |
Shares repurchased | $ (0.6) | (2.3) | | (39.5) | (42.4) |
Shares repurchased (in shares) | (0.6) | | | | |
Dividends | | | | (22.4) | (22.4) |
Balance at the end of the period at Jun. 30, 2023 | $ 26.3 | 282.7 | (7.9) | 1,988.9 | 2,290 |
Balance (in shares) at Jun. 30, 2023 | 35.3 | | | | |
Increase (Decrease) in Shareholders' Equity | | | | | |
Net income | | | | 119.9 | 119.9 |
Other comprehensive income (loss), net of tax | | | (1.4) | | (1.4) |
Share-based compensation | | 7.8 | | | 7.8 |
Shares issued, net of shares withheld for employee taxes | | (0.2) | | | (0.2) |
Shares repurchased | $ (0.1) | (1.2) | | (24.5) | $ (25.8) |
Shares repurchased (in shares) | (0.4) | | | | (0.3) |
Balance at the end of the period at Sep. 30, 2023 | $ 26.2 | $ 289.1 | $ (9.3) | $ 2,084.3 | $ 2,390.3 |
Balance (in shares) at Sep. 30, 2023 | 34.9 | | | | |