Goodwill and Other Intangible Assets - Other Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other intangible assets, net
Gross carrying value	$ 186,881	$ 186,881
Accumulated amortization	(40,504)	(18,513)
Net carrying amount	146,377	168,368
Estimated amortization expense for intangible assets
2021	20,136
2022	18,180
2023	16,868
2024	16,161
2025	15,425
Core deposit intangibles
Other intangible assets, net
Gross carrying value	141,232	141,232
Accumulated amortization	(29,971)	(11,016)
Net carrying amount	111,261	130,216
Program agreements
Other intangible assets, net
Gross carrying value	14,700	14,700
Accumulated amortization	(1,818)	(1,031)
Net carrying amount	12,882	13,669
Non-compete agreements
Other intangible assets, net
Gross carrying value	9,000	9,000
Accumulated amortization	(7,330)	(5,618)
Net carrying amount	1,670	3,382
Customer relationships
Other intangible assets, net
Gross carrying value	21,949	21,949
Accumulated amortization	(1,385)	(848)
Net carrying amount	$ 20,564	$ 21,101