Consolidated Statement of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest income
Loans and leases, including fees	$ 3,748,988	$ 3,975,053	$ 4,442,182
Investment securities
Fully taxable	141,046	176,469	288,532
Exempt from federal taxes	116	183	321
Deposits at banks	47,491	32,956	141,397
Other	1,143	8,051	7,161
Total interest income	3,938,784	4,192,712	4,879,593
Interest expense
Savings and interest-checking deposits	32,998	146,701	368,003
Time deposits	18,635	66,280	95,426
Deposits at Cayman Islands office	201	4,054	21,917
Short-term borrowings	7	28	24,741
Long-term borrowings	62,165	109,332	239,242
Total interest expense	114,006	326,395	749,329
Net interest income	3,824,778	3,866,317	4,130,264
Provision for credit losses	(75,000)	800,000	176,000
Net interest income after provision for credit losses	3,899,778	3,066,317	3,954,264
Other income
Brokerage services income	62,791	47,428	48,922
Trading account and foreign exchange gains	24,376	40,536	62,044
Gain (loss) on bank investment securities	(21,220)	(9,421)	18,037
Other revenues from operations	482,889	470,588	469,320
Total other income	2,166,994	2,088,444	2,061,679
Other expense
Salaries and employee benefits	2,045,677	1,950,692	1,900,797
Equipment and net occupancy	326,698	322,037	324,079
Outside data processing and software	291,839	258,480	229,731
FDIC assessments	69,704	53,803	41,535
Advertising and marketing	64,428	61,904	93,472
Printing, postage and supplies	36,507	39,869	39,893
Amortization of core deposit and other intangible assets	10,167	14,869	19,490
Other costs of operations	766,603	683,586	819,685
Total other expense	3,611,623	3,385,240	3,468,682
Income before taxes	2,455,149	1,769,521	2,547,261
Income taxes	596,403	416,369	618,112
Net income	1,858,746	1,353,152	1,929,149
Net income available to common shareholders
Basic	1,776,977	1,279,066	1,849,509
Diluted	$ 1,776,987	$ 1,279,068	$ 1,849,511
Net income per common share
Basic	$ 13.81	$ 9.94	$ 13.76
Diluted	$ 13.80	$ 9.94	$ 13.75
Mortgage Banking Revenues [Member]
Other income
Revenue from contract with customer	$ 571,329	$ 566,641	$ 457,770
Service Charges on Deposit Accounts [Member]
Other income
Revenue from contract with customer	402,113	370,788	432,978
Trust Income [Member]
Other income
Revenue from contract with customer	$ 644,716	$ 601,884	$ 572,608