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CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands | Total | Common stock | Paid-in capital | Treasury stock | Accumulated other comprehensive income (loss) | Retained earnings | ASU 2016-01 Accumulated other comprehensive income (loss) | ASU 2016-01 Retained earnings
--- | --- | --- | --- | --- | --- | --- | --- | ---
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |  |
Cumulative effect of accounting standard update |  |  |  |  |  |  | $ (18) | $ 18
Balance, beginning of year at Dec. 31, 2017 |  | $ 370,567 | $ 1,850,582 | $ 0 | $ (43,783) | $ 977,160 |  |
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |  |
Net common stock issued under share-based compensation plans |  | 786 | (8,917) |  |  |  |  |
Reacquisition of convertible junior subordinated debentures-equity component |  |  | 0 |  |  |  |  |
Reissuance of treasury stock, net under share-based compensation plans |  |  | 0 | 0 |  |  |  |
Equity compensation |  |  | 20,871 |  |  |  |  |
Purchases of common stock |  |  |  | (175,059) |  |  |  |
Other comprehensive income (loss) | $ (80,413) |  |  |  | (80,413) |  |  |
Net income | 670,097 |  |  |  |  | 670,097 |  |
Cash dividends |  |  |  |  |  | 0 |  |
Balance, end of year at Dec. 31, 2018 | 3,581,891 | 371,353 | 1,862,536 | (175,059) | (124,214) | 1,647,275 |  |
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |  |
Cumulative effect of accounting standard update |  |  |  |  | (18) |  |  |
Net common stock issued under share-based compensation plans |  | 0 | 0 |  |  |  |  |
Reacquisition of convertible junior subordinated debentures-equity component |  |  | 0 |  |  |  |  |
Reissuance of treasury stock, net under share-based compensation plans |  |  | (11,715) | 5,989 |  |  |  |
Equity compensation |  |  | 18,898 |  |  |  |  |
Purchases of common stock |  |  |  | (114,126) |  |  |  |
Other comprehensive income (loss) | 196,922 |  |  |  | 196,922 |  |  |
Net income | 673,763 |  |  |  |  | 673,763 |  |
Cash dividends |  |  |  |  |  | (42,388) |  |
Balance, end of year at Dec. 31, 2019 | 4,309,234 | 371,353 | 1,869,719 | (283,196) | 72,708 | 2,278,650 |  |
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |  |
Net common stock issued under share-based compensation plans |  | 0 | 0 |  |  |  |  |
Reacquisition of convertible junior subordinated debentures-equity component |  |  | (2,673) |  |  |  |  |
Reissuance of treasury stock, net under share-based compensation plans |  |  | (18,807) | 9,867 |  |  |  |
Equity compensation |  |  | 13,803 |  |  |  |  |
Purchases of common stock |  |  |  | (119,997) |  |  |  |
Other comprehensive income (loss) | 144,113 |  |  |  | 144,113 |  |  |
Net income | 446,093 |  |  |  |  | 446,093 |  |
Cash dividends | (82,600) |  |  |  |  | (82,647) |  |
Balance, end of year at Dec. 31, 2020 | $ 4,698,986 | $ 371,353 | $ 1,862,042 | $ (393,326) | $ 216,821 | $ 2,642,096 |  |

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