Debt Securities Available for Sale - Expected Maturities of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Amortized Cost
One year or less	$ 16,907
More than one year to five years	73,239
More than five years to ten years	79,916
Available-for-sale debt securities, allocated and single maturity date, total	170,062
Mortgage-backed securities and collateralized mortgage obligations	1,488,048
Amortized Cost	1,658,110	$ 1,701,379
Fair Value
One year or less	16,947
More than one year to five years	72,878
More than five years to ten years	75,530
Available-for-sale debt securities, allocated and single maturity date, total	165,355
Mortgage-backed securities and collateralized mortgage obligations	1,414,142
Fair Value	$ 1,579,497	$ 1,703,847

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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