Noninterest Income and Noninterest Expense (Components of Other Noninterest Income and Other Noninterest Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other noninterest income:
Income from bank-owned life insurance	$ 12,424	$ 11,473	$ 13,596
Credit-related fees	11,065	11,140	9,926
Other miscellaneous income	20,297	19,684	16,146
Total other noninterest income	43,786	42,297	39,668
Other noninterest expense:
Advertising	12,334	15,031	10,938
Corporate value and franchise taxes	13,595	12,797	8,741
Entertainment and contributions	11,359	8,260	7,122
Telecommunications and postage	14,659	14,686	13,146
Other retirement expense	(18,661)	(15,249)	(10,496)
Other miscellaneous expense	47,407	46,548	45,313
Total other noninterest expense	$ 80,693	$ 82,073	$ 74,764