Consolidated Statements of Income and Comprehensive Income (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income
Interest and fees on loans	$ 171,157	$ 171,242
Interest on taxable securities	6,118	10,082
Interest on nontaxable securities	141	157
Interest on deposits in other banks and federal funds sold	534	1,287
Total interest income	177,950	182,768
Interest expense
Interest on deposits	6,798	24,102
Interest on other borrowings	6,175	10,721
Total interest expense	12,973	34,823
Net interest income	164,977	147,945
Provision for loan losses	(16,579)	37,047
Provision for unfunded commitments	(11,839)	4,000
Provision for other credit losses	(173)	0
Provision for credit losses	(28,591)	41,047
Net interest income after provision for credit losses	193,568	106,898
Noninterest income
Service charges on deposit accounts	10,829	11,844
Mortgage banking activity	98,486	35,333
Other service charges, commissions and fees	1,016	961
Net loss on securities	(12)	(9)
Other noninterest income	7,654	6,250
Total noninterest income	117,973	54,379
Noninterest expense
Salaries and employee benefits	95,985	75,946
Occupancy and equipment	11,781	12,028
Data processing and communications expenses	11,884	11,954
Credit resolution-related expenses	547	2,198
Advertising and marketing	1,431	2,358
Amortization of intangible assets	4,126	5,631
Merger and conversion charges	0	540
Other noninterest expenses	23,044	27,398
Total noninterest expense	148,798	138,053
Income (loss) before income tax expense	162,743	23,224
Income tax expense	37,781	3,902
Net income	124,962	19,322
Other comprehensive income (loss)
Net unrealized holding gains (losses) arising during period on investment securities available for sale, net of tax expense (benefit) of $(1,972) and $5,756	(7,415)	21,653
Net unrealized losses on cash flow hedge during the period, net of tax benefit of $0 and $(26)	0	(97)
Total other comprehensive income (loss)	(7,415)	21,556
Comprehensive income	$ 117,547	$ 40,878
Basic earnings per common share (in dollars per share)	$ 1.80	$ 0.28
Diluted earnings per common share (in dollars per share)	$ 1.79	$ 0.28
Weighted average common shares outstanding
Basic (in shares)	69,392	69,248
Diluted (in shares)	69,741	69,502