Goodwill and Other Intangible Assets - Summary of gross carrying amounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other intangible assets
Gross carrying amount	$ 274,753	$ 274,869
Accumulated amortization	(185,977)	(158,419)
Net carrying amount	88,776	116,450
Amortization expense	27,558	33,205	$ 35,192
Fair value of SBA servicing assets	6,000	$ 6,100
Estimated amortization expense for other intangibles for each of the next five years
2024	22,395
2025	18,766
2026	15,232
2027	11,756
2028	8,020
Thereafter	6,655
Total estimated amortization expense for other intangibles for the next five years	$ 82,824
Minimum
Other intangible assets
Estimated useful lives	10 years
Maximum
Other intangible assets
Estimated useful lives	13 years
Core deposit intangibles | Minimum
Other intangible assets
Estimated useful lives	10 years
Core deposit intangibles | Maximum
Other intangible assets
Estimated useful lives	15 years
Customer lists
Other intangible assets
Estimated useful lives	15 years
Customer lists | Minimum
Other intangible assets
Estimated useful lives	10 years
Customer lists | Maximum
Other intangible assets
Estimated useful lives	15 years