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Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Statement of Financial Position [Abstract] |  |
Available for sale securities, amortized cost | $ 3,850,889 | $ 2,361,575
Allowance for expected credit losses | 0 | 552
Trading securities, cost | 45,307 | 47,907
Equity investments at fair value, cost | 210,320 | 113,709
Other investments, portion carried at fair value | $ 106,842 | $ 44,116
Common shares, par value (in usd per share) | $ 0.01 | $ 0.01
Common shares, shares authorized (in shares) | 100,000,000 | 100,000,000
Common shares, shares issued (in shares) | 63,308,434 | 63,217,708
Deferred tax expense (benefit) on accumulated other comprehensive income (loss) | $ 11,100 | $ 19,386
Treasury shares, number of shares (in shares) | 9,325,180 | 9,325,180

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