Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 235,952	$ 167,062
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of investment premiums, net	15,485	22,526
(Loss) gain on sale of investment securities, net	14	27
Gain on sale of other real estate owned, net	(324)	(620)
Valuation adjustment on other real estate owned	66	146
Provision for loan and lease losses	38,686	34,326
Change in cash surrender value of bank owned life insurance	(6,281)	(6,272)
Depreciation, amortization and accretion	40,015	43,628
(Gain) loss on sale of premises and equipment	(2,365)	1,127
Gain on store divestiture	(1,157)	0
Additions to residential mortgage servicing rights carried at fair value	(22,012)	(23,486)
Change in fair value of residential mortgage servicing rights carried at fair value	125	25,234
Gain on redemption of junior subordinated debentures at amortized cost	(1,043)	0
Change in junior subordinated debentures carried at fair value	0	4,666
Stock-based compensation	5,519	6,688
Net increase in equity and other investments	(123)	(955)
Unrealized holding losses on equity securities	(1,894)	0
Gain on sale of loans, net	(59,485)	(104,956)
Change in fair value of loans held for sale	1,103	(7,210)
Origination of loans held for sale	(2,283,639)	(2,563,978)
Proceeds from sales of loans held for sale	2,306,652	2,631,668
Change in other assets and liabilities:
Net decrease in other assets	6,167	47,757
Net increase (decrease) in other liabilities	43,380	(26,807)
Net cash provided by operating activities	318,601	250,517
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(283,948)	(783,430)
Proceeds from investment securities available for sale	341,680	437,007
Proceeds from investment securities held to maturity	385	392
Purchases of restricted equity securities	(45,601)	(243,171)
Redemption of restricted equity securities	48,840	243,190
Net change in loans and leases	(991,726)	(1,409,901)
Proceeds from sales of loans	119,783	220,235
Change in premises and equipment	(5,686)	(14,131)
Proceeds from bank owned life insurance death benefits	1,481	373
Proceeds from sales of other real estate owned	2,805	5,825
Net cash paid in store divestiture	(35,219)	0
Net cash used in investing activities	(847,206)	(1,543,611)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposit liabilities	981,648	831,811
Net decrease in securities sold under agreements to repurchase	(7,324)	(31,406)
Proceeds from term debt borrowings	50,000	205,000
Repayment of term debt borrowings	(100,652)	(205,000)
Repayment of junior subordinated debentures at amortized cost	(10,598)	0
Dividends paid on common stock	(127,662)	(105,748)
Proceeds from stock options exercised	1,065	548
Repurchase and retirement of common stock	(12,893)	(5,977)
Net cash provided by financing activities	773,584	689,228
Net increase (decrease) in cash and cash equivalents	244,979	(603,866)
Cash and cash equivalents, beginning of period	634,280	1,449,432
Cash and cash equivalents, end of period	879,259	845,566
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	83,255	58,191
Income taxes	49,475	25,668
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized gains on investment securities available for sale, net of taxes	(56,219)	13,819
Change in unrealized gains on junior subordinated debentures carried at fair value, net of taxes	(4,174)	0
Junior subordinated debentures, at fair value, cumulative effect adjustment	9,710	0
Cash dividend declared on common stock and payable after period-end	46,253	39,649
Change in GNMA mortgage loans recognized due to repurchase option	(4,407)	1,445
Transfer of loans to other real estate owned	2,587	2,851
Real Estate Owned, Transfer from Real Estate Owned	$ 0	$ 78