Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INTEREST INCOME
Interest and fees on loans and leases	$ 890,515	$ 951,439	$ 1,051,077
Interest and dividends on investment securities:
Taxable	60,399	47,739	56,150
Exempt from federal income tax	5,947	6,095	7,400
Dividends	1,318	2,615	2,269
Interest on temporary investments and interest bearing deposits	3,864	4,739	14,180
Total interest income	962,043	1,012,627	1,131,076
INTEREST EXPENSE
Interest on deposits	27,151	100,200	167,941
Interest on securities sold under agreement to repurchase and federal funds purchased	280	766	2,092
Interest on borrowings	2,838	13,921	17,564
Interest on junior subordinated debentures	12,127	15,221	22,845
Total interest expense	42,396	130,108	210,442
Net interest income	919,647	882,519	920,634
(Recapture) provision for credit losses	(42,651)	204,861	72,515
Net interest income after provision for credit losses	962,298	677,658	848,119
NON-INTEREST INCOME
Revenue from Contract with Customer	83,312	84,627	94,544
Residential mortgage banking revenue, net	186,811	270,822	101,810
Gain (loss) on sale of debt securities, net	8	190	(7,184)
(Loss) gain on equity securities, net	(1,511)	769	83,475
Gain on loan and lease sales, net	15,715	6,707	10,467
BOLI income	8,302	8,399	8,406
Other income	63,681	40,495	48,306
Total non-interest income	356,318	412,009	339,824
NON-INTEREST EXPENSE
Salaries and employee benefits	480,820	479,247	420,373
Occupancy and equipment, net	137,546	151,650	144,236
Communications	11,564	11,843	14,583
Marketing	7,381	8,313	13,255
Services	48,800	46,640	54,111
FDIC assessments	9,238	12,516	11,233
Intangible amortization	4,520	4,986	5,618
Merger related expenses	15,183	0	0
Goodwill impairment	0	1,784,936	0
Other expenses	45,404	45,956	55,631
Total non-interest expense	760,456	2,546,087	719,040
Income (loss) before provision for income taxes	558,160	(1,456,420)	468,903
Provision for income taxes	137,860	67,000	114,808
Net Income (Loss) Attributable to Parent, Total	$ 420,300	$ (1,523,420)	$ 354,095
Earnings Per Share [Abstract]
Basic earnings per common share (usd per share)	$ 1.92	$ (6.92)	$ 1.61
Diluted earnings per common share (usd per share)	$ 1.91	$ (6.92)	$ 1.60
Weighted average number of common shares outstanding:
Basic (in shares)	219,032	220,218	220,339
Diluted (in shares)	219,581	220,218	220,650
Service charges on deposits
NON-INTEREST INCOME
Revenue from Contract with Customer	$ 42,086	$ 40,838	$ 45,616
Card-based fees
NON-INTEREST INCOME
Revenue from Contract with Customer	36,114	28,190	33,051
Brokerage revenue
NON-INTEREST INCOME
Revenue from Contract with Customer	$ 5,112	$ 15,599	$ 15,877