Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income	$ 170,612	$ 171,561
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	35,204	13,389
Depreciation, amortization and accretion, net	43,322	31,986
Stock-based compensation expense	6,283	7,098
Net amortization of premium on securities	2,971	4,069
Accretion of discount on loans	(11,746)	(9,860)
Mortgage servicing rights fair value change, net	19,122	(3,664)
Originations and purchases of mortgage loans held-for-sale	(1,832,264)	(1,875,225)
Proceeds from sales of mortgage loans held-for-sale	1,736,063	1,770,257
Bank owned life insurance (BOLI) income	(2,740)	(2,258)
(Increase) decrease in trading securities, net	(738)	133
Net (increase) decrease in brokerage customer receivables	(960)	9,782
Gains on mortgage loans sold	(51,086)	(49,200)
(Gains) losses on investment securities, net	(2,228)	339
Losses on sales of premises and equipment, net	37	18
Net losses on sales and fair value adjustments of other real estate owned	1,115	3,008
Increase in accrued interest receivable and other assets, net	(139,971)	(61,562)
Increase in accrued interest payable and other liabilities, net	49,233	92,374
Net Cash Provided by Operating Activities	22,229	102,245
Investing Activities:
Proceeds from maturities and calls of available-for-sale securities	231,198	133,209
Proceeds from maturities and calls of held-to-maturity securities	51,393	6,014
Proceeds from sales of available-for-sale securities	667,918	208,991
Proceeds from sales of equity securities with readily determinable fair value	11,000	0
Proceeds from sales and capital distributions of equity securities without readily determinable fair value	609	616
Purchases of available-for-sale securities	(871,269)	(475,998)
Purchases of held-to-maturity securities	(178,331)	(70,993)
Purchases of equity securities with readily determinable fair value	(18,677)	0
Purchases of equity securities without readily determinable fair value	(1,072)	(2,741)
Purchases of Federal Home Loan Bank and Federal Reserve Bank stock, net	(672)	(6,710)
Distributions from investments in partnerships, net	772	479
Net cash received (paid) in business combinations	748	(18,708)
Proceeds from sales of other real estate owned	5,155	8,236
Net increase in interest bearing deposits with banks	(337,581)	(160,456)
Net increase in loans	(1,340,204)	(937,503)
Redemption of BOLI	0	2,121
Purchases of premises and equipment, net	(31,297)	(32,318)
Net Cash Used for Investing Activities	(1,810,310)	(1,345,761)
Financing Activities:
Increase in deposit accounts	1,262,941	1,182,140
Increase (decrease) in other borrowings, net	16,243	(4,489)
Increase in Federal Home Loan Bank advances, net	148,441	107,000
Proceeds from the issuance of subordinated notes, net	296,741	0
Cash payments to settle contingent consideration liabilities recognized in business combinations	(66)	0
Issuance of common shares resulting from the exercise of stock options, employee stock purchase plan and conversion of common stock warrants	5,978	11,747
Common stock repurchases for tax withholdings related to stock-based compensation	(1,016)	(369)
Dividends paid	(32,389)	(25,462)
Net Cash Provided by Financing Activities	1,696,873	1,270,567
Net (Decrease) Increase in Cash and Cash Equivalents	(91,208)	27,051
Cash and Cash Equivalents at Beginning of Period	392,200	277,591
Cash and Cash Equivalents at End of Period	$ 300,992	$ 304,642