Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income, Before-tax Amount	$ 80,835	$ 80,091
Net income, Tax (Expense) Benefit	(18,204)	(17,791)
Net of tax	62,631	62,300
Unrealized gains (losses) on available-for-sale securities:
Unrealized holding gains, Before-tax Amount		43,279
Unrealized holding gains, Tax (Expense) Benefit		(10,284)
Unrealized holding gains, Net of Tax Amount		32,995
Reclassification adjustment for losses included in net income, Before-tax Amount		1,644
Reclassification adjustment for losses included in net income, Tax (Expense) Benefit	0	(374)
Reclassification adjustment for losses included in net income, Net of Tax Amount		1,270
Net unrealized gains, Before-tax Amount	356	44,923
Net unrealized gains, Tax (Expense) Benefit	(209)
Net unrealized gains, Tax (Expense) Benefit		(10,658)
Net unrealized gains, Net of Tax Amount	147	34,265
Amortization of unrealized losses on held-to-maturity securities transferred from available-for-sale, Before-tax amount	2,063
Amortization of unrealized losses on held-to-maturity securities transferred from available-for-sale, Tax (Expense) Benefit	(493)
Amortization of unrealized losses on held-to-maturity securities transferred from available-for-sale, Net of Tax Amount	1,570
Unrealized losses on held-to-maturity securities transferred from available-for-sale:
Amortization of unrealized losses, Before-tax Amount		2,968
Amortization of unrealized losses, Tax (Expense) Benefit		(720)
Amortization of unrealized losses, Net of Tax Amount		2,248
Derivative instruments designated as cash flow hedges:
Unrealized holding gains (losses) on derivatives, Before-tax Amount	2,524	(1,202)
Unrealized holding gains (losses) on derivatives, Tax (Expense) Benefit	(645)	307
Unrealized holding gains (losses) on derivatives, Net of Tax Amount	1,879	(895)
Gains on derivative instruments realized in net income, Before-tax Amount	(1,440)	(822)
Gains on derivative instruments realized in net income, Tax (Expense) Benefit	368	210
Gains on derivative instruments realized in net income, Net of Tax Amount	(1,072)	(612)
Net cash flow hedge activity, Before-tax Amount	1,084	(2,024)
Net cash flow hedge activity, Tax (Expense) Benefit	(277)	517
Net cash flow hedge activity, Net of tax Amount	807	(1,507)
Amortization of defined benefit pension plan net periodic pension cost components, Before-tax Amount	44	61
Amortization of defined benefit pension plan net periodic pension cost components, Tax (Expense) Benefit	(11)	(16)
Amortization of defined benefit pension plan net periodic pension cost components, Net of Tax Amount	33	45
Total other comprehensive income, Before-tax Amount	3,547	45,928
Total other comprehensive income, Tax (Expense) Benefit	(990)	(10,877)
Total other comprehensive income, Net of Tax Amount	2,557	35,051
Comprehensive income, Before-tax Amount	84,382	126,019
Comprehensive income, Tax (Expense) Benefit	(19,194)	(28,668)
Comprehensive income, Net of Tax Amount	$ 65,188	$ 97,351