Goodwill and Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of core deposit intangibles and other intangibles
Amortization of other intangible assets	$ 10,192	$ 9,948	$ 8,159
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Summary of core deposit intangibles and other intangibles
Reductions due to sale	(17,435)	(217)	(43)
Core Deposits [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount at the beginning of the year		80,730	58,100	$ 0
Accumulated amortization	(21,205)	(12,456)	(5,326)
Total Estimated Amortization Expense	66,904	68,274	52,774
Amortization of other intangible assets	8,749	7,130	5,326
Adjustments to Core Deposits [Member]
Summary of core deposit intangibles and other intangibles
Additions during the period	7,379	22,630	58,100
Other Intangible Assets [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount at the beginning of the year		38,970	44,887	$ 34,572
Additions during the period	200	0	10,359
Accumulated amortization	(20,385)	(24,643)	(21,825)
Total Estimated Amortization Expense	1,350	20,027	23,062
Amortization of other intangible assets	$ 1,443	$ 2,818	$ 2,833