Statements of Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Statement of cash flows specific transaction amounts [Abstract]
Income taxes paid	$ 23,309	$ 5,336
Interest expense paid on deposits and borrowings	26,808	43,004
Noncash transfers from loans to other real estate	406	2,101
Finance right-of-use assets resulting from lease liabilities		10,698
Operating right-of-use assets resulting from lease liabilities	$ 671	$ 32,762