Other Noninterest Income and Other Noninterest Expense (Components of Other Noninterest Income and Other Noninterest Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other noninterest income:
Income from bank-owned life insurance	$ 13,596	$ 10,881	$ 10,314
Credit related fees	9,926	11,057	11,121
Income from derivatives	5,196	2,745	1,645
Gain on sales of assets	7,814	186	1,279
Safety deposit box income	1,696	1,758	1,830
Other miscellaneous income	9,254	9,334	9,249
Total other noninterest income	47,482	35,961	35,438
Other noninterest expense:
Advertising	10,938	11,225	8,937
Ad valorem and franchise taxes	8,741	10,498	10,492
Printing and supplies	4,422	4,851	4,550
Insurance expense	3,275	3,482	3,919
Travel	4,268	5,331	4,066
Entertainment and contributions	7,122	6,723	5,762
Tax credit investment amortization	4,263	8,513	8,817
Other miscellaneous expense	29,535	21,580	30,585
Total other noninterest expense	$ 72,564	$ 72,203	$ 77,128