Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended					12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 1,320,799,000		$ 1,319,598,000			$ 1,320,799,000	$ 1,319,598,000
Goodwill increase						1,200,000
Goodwill impairment	$ 0	$ 0	$ 0	$ 0	$ 0	0	0	$ 0
Amortization of intangibles						$ 16,306,000	15,915,000	13,494,000
Minimum
Goodwill [Line Items]
Useful life (in years)	8 years					8 years
Maximum
Goodwill [Line Items]
Useful life (in years)	15 years					15 years
Core Deposit Premium
Goodwill [Line Items]
Amortization of intangibles						$ 14,672,000	14,346,000	12,100,000
Core Deposit Premium | Minimum
Goodwill [Line Items]
Useful life (in years)	10 years					10 years
Core Deposit Premium | Maximum
Goodwill [Line Items]
Useful life (in years)	15 years					15 years
Books of Business Intangible
Goodwill [Line Items]
Amortization of intangibles						$ 1,634,000	$ 1,569,000	$ 1,400,000