Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest income
Interest and fees on loans	$ 1,228,480	$ 1,044,502	$ 856,549
Mortgage loans held-for-sale	11,992	15,738	12,332
Interest bearing deposits with banks	29,803	17,090	9,252
Federal funds sold and securities purchased under resale agreements	700	1	2
Investment securities	108,046	87,382	63,315
Trading account securities	39	43	25
Federal Home Loan Bank and Federal Reserve Bank stock	5,416	5,331	4,370
Brokerage customer receivables	666	723	623
Total interest income	1,385,142	1,170,810	946,468
Interest expense
Interest on deposits	278,892	166,553	83,326
Interest on Federal Home Loan Bank advances	9,878	12,412	8,798
Interest on other borrowings	13,897	8,599	5,370
Interest on subordinated notes	15,555	7,121	7,116
Interest on junior subordinated debentures	12,001	11,222	9,782
Total interest expense	330,223	205,907	114,392
Net interest income	1,054,919	964,903	832,076
Provision for credit losses	53,864	34,832	29,768
Net interest income after provision for credit losses	1,001,055	930,071	802,308
Non-interest income
Revenue from contracts with customers	161,465	152,513	138,994
Mortgage banking	154,293	136,990	113,472
Gains (losses) on investment securities, net	3,525	(2,898)	45
Fees from covered call options	3,670	3,519	4,402
Trading (losses) gains, net	(158)	11	(845)
Operating lease income, net	47,041	38,451	29,646
Other	62,617	52,710	56,507
Total non-interest income	407,172	356,150	319,506
Non-interest expense
Salaries and employee benefits	546,420	480,077	430,078
Equipment	52,328	42,949	38,358
Operating lease equipment	35,760	29,305	24,107
Occupancy, net	64,289	57,814	52,920
Data processing	27,820	35,027	31,495
Advertising and marketing	48,595	41,140	30,830
Professional fees	27,471	32,306	27,835
Amortization of other intangible assets	11,844	4,571	4,401
FDIC insurance	9,199	17,209	16,231
OREO expenses, net	3,628	6,120	3,593
Other	100,772	79,570	71,969
Total non-interest expense	928,126	826,088	731,817
Income before taxes	480,101	460,133	389,997
Income tax expense	124,404	116,967	132,315
Net income	355,697	343,166	257,682
Preferred stock dividends	8,200	8,200	9,778
Net income applicable to common shares	$ 347,497	$ 334,966	$ 247,904
Net income per common share - Basic (usd per share)	$ 6.11	$ 5.95	$ 4.53
Net income per common share - Diluted (usd per share)	6.03	5.86	4.40
Cash dividends declared per common share (usd per share)	$ 1.00	$ 0.76	$ 0.56
Weighted average common shares outstanding (in shares)	56,857	56,300	54,703
Dilutive potential common shares (in shares)	762	908	1,983
Average common shares and dilutive common shares (in shares)	57,619	57,208	56,686
Wealth management
Non-interest income
Revenue from contracts with customers	$ 97,114	$ 90,963	$ 81,766
Service charges on deposit accounts
Non-interest income
Revenue from contracts with customers	$ 39,070	$ 36,404	$ 34,513