Investment Securities - Held-to-Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2022		Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	[1]	$ 2,270,635
Debt Securities, Held-to-maturity, Allowance for Credit Loss	[1]	(1,500)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		2,269,135	[1]	$ 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	[1]	8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	[1]	(158,671)
Debt Securities, Held-to-maturity, Fair Value	[1]	2,110,472
US States and Political Subdivisions Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		1,243,443
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(140)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		1,243,303
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(77,526)
Debt Securities, Held-to-maturity, Fair Value		1,165,785
Commercial Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		427,411
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		427,411
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(34,287)
Debt Securities, Held-to-maturity, Fair Value		393,124
Mortgage-backed Securities, Issued by Private Enterprises
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		345,825
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		345,825
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(26,027)
Debt Securities, Held-to-maturity, Fair Value		319,798
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		184,162
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		184,162
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(12,462)
Debt Securities, Held-to-maturity, Fair Value		171,700
Corporate Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		69,794
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(1,360)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		68,434
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Interest Receivable		13,500
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(8,369)
Debt Securities, Held-to-maturity, Fair Value		$ 60,065

[1] Excludes accrued interest receivable of $13.5 million at December 31, 2022 which is recorded in "Other assets" on the consolidated balance shee