Summary of Significant Accounting Policies - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity Securities	$ 2,636,673	$ 2,683,241
Threshold Net Book Balance, Individually Evaluated Loans	1,000
Financing Receivable, Threshold Loss on Modifications Estimated	1,000
Interest Receivable	109,400	105,400
Liability Recorded for Expected Credit Losses on Unfunded Commitments	85,100
Other Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accrued interest receivable for investment securities	26,400	28,200
Interest Receivable	109,400	105,400
Other Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Liability Recorded for Expected Credit Losses on Unfunded Commitments	$ 85,100	$ 67,200