Securities - Credit Quality Indicator (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 1,087,209	$ 942,314
Investment And Mortgage-Backed Securities
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	383,269
Investment And Mortgage-Backed Securities | AAA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	44,532
Investment And Mortgage-Backed Securities | AA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	160,389
Investment And Mortgage-Backed Securities | A
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	84,954
Investment And Mortgage-Backed Securities | BBB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	82,060
Investment And Mortgage-Backed Securities | BB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	11,334
Securities investment | State, municipal and sovereign debt obligations
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	278,179	238,405
Securities investment | State, municipal and sovereign debt obligations | AAA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	33,421
Securities investment | State, municipal and sovereign debt obligations | AA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	138,734
Securities investment | State, municipal and sovereign debt obligations | A
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	72,959
Securities investment | State, municipal and sovereign debt obligations | BBB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	33,065
Securities investment | State, municipal and sovereign debt obligations | BB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	0
Securities investment | Corporate debt securities
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	72,821	$ 72,305
Securities investment | Corporate debt securities | AAA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	0
Securities investment | Corporate debt securities | AA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	497
Securities investment | Corporate debt securities | A
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	11,995
Securities investment | Corporate debt securities | BBB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	48,995
Securities investment | Corporate debt securities | BB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	11,334
Other
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	32,269
Other | AAA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	11,111
Other | AA
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	21,158
Other | A
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	0
Other | BBB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	0
Other | BB
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 0