Goodwill and Other Intangible Assets - Other Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other intangible assets, net
Gross Amount	$ 186,881	$ 27,599
Accumulated Amortization	(18,513)	(7,103)
Other intangible assets, net	168,368	20,496
Estimated amortization expense for intangible assets
Estimated amortization expense for 2020	21,992
2021	20,136
2022	18,180
2023	16,868
2024	16,161
Core deposit intangibles
Other intangible assets, net
Gross Amount	141,232	3,049
Accumulated Amortization	(11,016)	(2,502)
Other intangible assets, net	130,216	547
Program agreements
Other intangible assets, net
Gross Amount	14,700	14,700
Accumulated Amortization	(1,031)	(408)
Other intangible assets, net	13,669	14,292
Non-compete agreements
Other intangible assets, net
Gross Amount	9,000	9,250
Accumulated Amortization	(5,618)	(3,643)
Other intangible assets, net	3,382	5,607
Customer relationships
Other intangible assets, net
Gross Amount	21,949	600
Accumulated Amortization	(848)	(550)
Other intangible assets, net	$ 21,101	$ 50