Business Segments - Operating Results and Other Key Financial Measures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information
Net interest income before (reversal of) provision for credit losses	$ 2,045,881	$ 1,531,571	$ 1,377,193
(Reversal of) provision for credit losses	73,500	(35,000)	210,653
Noninterest income	298,666	285,895	235,547
Noninterest expense	859,393	796,089	716,322
INCOME BEFORE INCOME TAXES	1,411,654	1,056,377	685,765
Segment net income	1,128,083	872,981	567,797
Segment assets	64,112,150	60,870,701	52,156,913
Consumer and Business Banking
Segment Reporting Information
Net interest income before (reversal of) provision for credit losses	1,170,850	697,101	530,829
(Reversal of) provision for credit losses	27,197	(4,998)	3,885
Noninterest income	110,139	94,125	64,115
Noninterest expense	397,882	364,635	331,750
INCOME BEFORE INCOME TAXES	855,910	431,589	259,309
Segment net income	608,120	308,630	185,782
Segment assets	17,385,804	14,961,809	13,351,060
Commercial Banking
Segment Reporting Information
Net interest income before (reversal of) provision for credit losses	892,386	766,202	706,286
(Reversal of) provision for credit losses	46,303	(30,002)	206,768
Noninterest income	179,248	163,768	142,337
Noninterest expense	314,185	275,649	266,923
INCOME BEFORE INCOME TAXES	711,146	684,323	374,932
Segment net income	507,467	489,233	268,476
Segment assets	33,042,785	28,556,706	26,958,766
Other
Segment Reporting Information
Net interest income before (reversal of) provision for credit losses	(17,355)	68,268	140,078
(Reversal of) provision for credit losses	0	0	0
Noninterest income	9,279	28,002	29,095
Noninterest expense	147,326	155,805	117,649
INCOME BEFORE INCOME TAXES	(155,402)	(59,535)	51,524
Segment net income	12,496	75,118	113,539
Segment assets	$ 13,683,561	$ 17,352,186	$ 11,847,087