Acquisition and Divestiture Activity ( Unaudited Pro Forma Results) (Details) - BBVA USA Bancshares, Inc. - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Business Acquisition [Line Items]
Net interest income	$ 2,984,000	$ 3,126,000	$ 5,975,000	$ 6,250,000
Noninterest income	2,258,000	1,757,000	4,354,000	3,825,000
Net income	$ 2,097,000	$ 3,327,000	$ 4,226,000	$ 851,000