Investment Securities Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 01, 2019
HTM, at amortized cost	$ 980,384	$ 278,281
Estimated Fair Value	965,867
Net gains (losses) on other securities	(400)
Proceeds from sales of AFS securities	359,137	215,150	$ 710,739
Visa
Gain on sale of Visa shares	34,000
Collateral Pledged
Available-for-sale securities pledged as collateral	2,502,100	520,500
Debt securities
HTM, at amortized cost		79,000
Estimated Fair Value		82,000
Net investment securities gains		3,000
Prepayment penalty on FHLB advances		$ 2,900
Auction rate securities
Proceeds from sales of AFS securities	$ 24,600
Accounting Standards Update 2019-04 | State and municipal securities
HTM, at amortized cost				$ 158,900
Estimated Fair Value				$ 168,500