Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Goodwill [Line Items]
Goodwill	$ 901,312,000		$ 901,312,000		$ 901,312,000
Goodwill adjustments during period	0	$ 0	0	$ 0
Accumulated impairment loss	0		0
Net intangible assets	46,307,000	$ 59,028,000	46,307,000	$ 59,028,000	55,600,000
Estimated amortization expense for 2023					12,300,000
Estimated amortization expense for 2024					11,100,000
Estimated amortization expense for 2025					10,000,000
Estimated amortization expense for 2026					8,900,000
Estimated amortization expense for 2027					7,200,000
Core Deposits
Goodwill [Line Items]
Net intangible assets	44,200,000		$ 44,200,000		53,200,000
Core Deposits | Minimum
Goodwill [Line Items]
Weighted average useful life (in years)			6 years
Core Deposits | Maximum
Goodwill [Line Items]
Weighted average useful life (in years)			11 years
Customer Relationships
Goodwill [Line Items]
Net intangible assets	$ 2,100,000		$ 2,100,000		$ 2,400,000