Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans and leases	$ 993,138	$ 1,097,845	$ 1,047,969
Investment securities	106,770	115,569	111,619
Deposits in financial institutions	3,583	6,479	2,082
Total interest income	1,103,491	1,219,893	1,161,670
Interest expense:
Deposits	59,663	148,460	80,140
Borrowings	8,161	26,961	11,985
Subordinated debentures	21,109	29,843	28,631
Total interest expense	88,933	205,264	120,756
Net interest income	1,014,558	1,014,629	1,040,914
Provision for credit losses	339,000	22,000	45,000
Net interest income after provision for credit losses	675,558	992,629	995,914
Noninterest income:
Other commissions and fees	40,347	43,623	45,543
Leased equipment income	43,628	38,727	37,881
Service charges on deposit accounts	10,351	14,637	16,509
Gain on sale of loans and leases	2,139	1,114	4,675
Gain on sale of securities	13,171	25,445	8,176
Other income	36,424	19,016	35,851
Total noninterest income	146,060	142,562	148,635
Noninterest expense:
Compensation	271,494	285,862	282,568
Occupancy	57,555	57,407	53,223
Data processing	26,779	27,556	27,225
Other professional services	19,917	17,803	21,952
Insurance and assessments	22,625	16,404	20,705
Customer related expense	14,753	18,726	22,506
Loan expense	28,865	24,016	21,371
Foreclosed assets income, net	(17)	(3,555)	(751)
Customer Related Expense	17,532	13,839	10,353
Loan expense	13,454	12,931	10,569
Acquisition, integration and reorganization costs	1,060	349	1,770
Goodwill impairment	1,470,000	0	0
Other expense	40,002	30,913	39,741
Total noninterest expense	1,984,019	502,251	511,232
Earnings (loss) before income taxes	(1,162,401)	632,940	633,317
Income tax expense	(75,173)	(164,304)	(167,978)
Net earnings (loss)	$ (1,237,574)	$ 468,636	$ 465,339
Earnings Per Share, Basic (usd per share)	$ (10.61)	$ 3.90	$ 3.72
Diluted income per share (usd per share)	(10.61)	3.90	3.72
Dividends declared per share (usd per share)	$ 2.30	$ 2.40	$ 1.35