Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Statement of cash flows specific transaction amounts [Abstract]
Income taxes paid	$ 17,277	$ 11,629
Interest expense paid on deposits and borrowings	64,881	46,506
Noncash transfers from loans to other real estate	5,684	$ 10,368
Finance right-of-use assets resulting from lease liabilities	9,823
Operating right-of-use assets resulting from lease liabilities	$ 33,180		$ 33,900