Debt Securities Available for Sale - Expected Maturities of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Amortized Cost
One year or less	$ 5,912
More than one year to five years	80,419
More than five years to ten years	61,557
Available-for-sale debt securities, allocated and single maturity date, total	147,888
Mortgage-backed securities and collateralized mortgage obligations	1,553,491
Amortized Cost	1,701,379	$ 1,277,511
Fair Value
One year or less	5,998
More than one year to five years	82,493
More than five years to ten years	60,997
Available-for-sale debt securities, allocated and single maturity date, total	149,488
Mortgage-backed securities and collateralized mortgage obligations	1,554,359
Debt securities available for sale, at fair value	$ 1,703,847	$ 1,316,952

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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