Consolidated Balance Sheets (Parenthetical) - USD ($) $ / shares in Thousands, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Amortized Cost	$ 4,773,742	$ 4,997,529
Debt Securities, Held-to-maturity, Fair Value	$ 2,071,051	$ 0
Preferred Stock, No Par Value	$ 0	$ 0
Common Stock, No Par Value	$ 0	$ 0

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

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Face amount per share of no-par value common stock.

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

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Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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