CONSOLIDATED STATEMENTS OF INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest incomeand divided income:
Loans	$ 553,647	$ 532,684	$ 531,022
Investment securities	60,224	51,125	50,905
Money martket investments and interest-bearing cash accounts	11,096	4,614	3,365
Total interest income	624,967	588,423	585,292
Interest expense:
Deposits	67,651	66,537	67,302
Securities sold under agreements to repurchase	9,401	10,911	20,203
Advances from FHLB	13,549	11,140	5,964
Other borrowings	8,983	8,284	7,705
Total interest expense	99,584	96,872	101,174
Net interest income	525,383	491,551	484,118
Provision for loan and lease losses	59,253	144,254	86,733
Net interest income after provision for loan and lease losses	466,130	347,297	397,385
Non-interest income:
Mortgage banking activities	17,228	13,491	20,435
Net (loss) gain on sale of investments	(34)	371	6,104
Gain From Recovery Of Investments Previously Written Off	0	0	1,547
Other-than-temporary impairment (OTTI) losses on available-for-sale debt securities:
Total OTTI losses	0	(12,231)	(1,845)
Portion of OTTI recognized in other comprehensive income (OCI)	(50)	0	(4,842)
Net impairment losses recognized in earnings	(50)	(12,231)	(6,687)
Gain on early extinguishment of debt	2,316	1,391	4,217
Insurance commission income	8,429	8,197	8,473
Other non-interest income	32,742	28,854	30,900
Total non-interest income	82,310	62,387	87,954
Non-interest expenses:
Employees' compensation and benefits	159,494	151,845	151,493
Occupancy and equipment	57,942	56,659	55,159
Business promotion	14,808	12,485	11,419
Professional fees	43,497	45,929	44,137
Taxes, other than income taxes	14,707	14,550	15,139
FDIC deposit insurance	8,909	13,725	20,055
Net loss on other real estate owned (OREO) and OREO operations	14,452	10,997	11,533
Credit and debit card processing expenses	15,546	13,212	13,635
Communications	6,372	6,148	6,759
Other non-interest expenses	22,075	22,151	25,751
Total non-interest expenses	357,802	347,701	355,080
Income before income taxes	190,638	61,983	130,259
Income tax (benefit) expense	(10,970)	(4,973)	37,030
Net income	201,608	66,956	93,229
Net income attributable to common stockholders	$ 198,932	$ 64,280	$ 93,006
Net income per common share:
Basic	$ 0.92	$ 0.3	$ 0.44
Diluted	$ 0.92	$ 0.3	$ 0.43
Deposit Account [Member]
Non-interest income:
Service charges and fees on deposits accounts	$ 21,679	$ 22,314	$ 22,965
Other-than-temporary impairment (OTTI) losses on available-for-sale debt securities:
Total non-interest income	$ 21,668