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CONSOLIDATED STATEMENTS OF CONDITION (Parenthetical) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Assets: |  |
Available-for-sale investment securities, cost | $ 4,406,878 | $ 3,427,779
Equity and other securities, cost | $ 44,069 | $ 46,511
Shareholders' equity: |  |
Preferred stock, par value (in dollars per share) | $ 1.00 | $ 1.00
Preferred stock, shares authorized (in shares) | 500,000 | 500,000
Preferred stock, shares issued (in shares) | 0 | 0
Common stock, par value (in dollars per share) | $ 1.00 | $ 1.00
Common stock, shares authorized (in shares) | 75,000,000 | 75,000,000
Common stock, shares issued (in shares) | 54,071,989 | 53,754,599
Treasury stock, shares at cost (in shares) | 146,002 | 161,472
Shares held by deferred compensation arrangements (in shares) | 145,987 | 161,457

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