Investment Securities - Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	$ 44,778	$ 49,545
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, 12 Months or Longer	281,447	258,411
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	326,225	307,956
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	868,269	247,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	868,269	247,182
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	643	1,493
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, 12 Months or Longer	9,739	12,565
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	10,382	14,058
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	341	124
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	341	124
Treasury notes
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	29,757	29,560
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, 12 Months or Longer	5,862	5,798
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	35,619	35,358
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	588	762
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, 12 Months or Longer	131	193
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	719	955
Federal agencies
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	14,947	19,276
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, 12 Months or Longer	275,385	252,613
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	290,332	271,889
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	53	724
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, 12 Months or Longer	9,606	12,372
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	9,659	13,096
Mortgage-backed - Government-sponsored entity (GSE)
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	74	709
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, 12 Months or Longer	200
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	274	709
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	1,482	247,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	1,482	247,182
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	2	7
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, 12 Months or Longer	2
Available-for-sale securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	4	7
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	56	124
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	56	$ 124
Mortgage-backed - Non-GSE residential
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value
Held-to-maturity securities, Continuous Unrealized Loss Position, Fair Value, Less than 12 Months	866,787
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	866,787
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Less than 12 Months	285
Held-to-maturity securities, Continuous Unrealized Loss Position, Gross Unrealized Losses, Total	$ 285