Consolidated Statements of Condition (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Consolidated Statements of Condition
Held to maturity, Fair value (in dollars)	$ 2,400	$ 1,200
Available for sale, Amortized cost (in dollars)	$ 3,187,248	$ 3,481,165
Common shares, par value (in dollars per share)	$ 1.00	$ 1.00
Common shares, Authorized shares	275,000,000	275,000,000
Common shares, issued shares	96,191,692	96,104,029
Treasury, shares	31,014,374	30,494,143

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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-Name Accounting Standards Codification
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Number of previously issued common shares repurchased by the issuing entity and held in treasury.

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-Name Accounting Standards Codification
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-SubTopic 10
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