Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 185,843	$ 144,971
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of investment premiums, net	12,338	18,750
Loss (gain) on sale of investment securities, net	7,186	(14)
Gain on sale of other real estate owned, net	(107)	(196)
Valuation adjustment on other real estate owned	2,734	66
Provision for loan and lease losses	33,036	26,975
Change in cash surrender value of bank owned life insurance	(4,267)	(4,203)
Depreciation, amortization and accretion	22,600	27,411
Gain on sale of premises and equipment	(687)	(1,789)
Gain on store divestiture	(1,225)	0
Additions to residential mortgage servicing rights carried at fair value	(9,379)	(13,390)
Change in fair value of residential mortgage servicing rights carried at fair value	38,624	324
Gain on redemption of junior subordinated debentures at amortized cost	0	(1,043)
Stock-based compensation	3,476	3,379
Net increase in equity and other investments	(3,068)	(1,504)
Gain (loss) on equity securities, net	(83,302)	1,432
Gain on sale of loans and leases, net	(34,471)	(33,746)
Change in fair value of loans held for sale	(7,685)	(5,402)
Origination of loans held for sale	(1,185,240)	(1,526,715)
Proceeds from sales of loans held for sale	1,033,110	1,390,161
Change in other assets and liabilities:
Net increase in other assets	(114,975)	(13,585)
Net (decrease) increase in other liabilities	(12,309)	37,491
Net cash (used in) provided by operating activities	(117,768)	49,373
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(322,410)	(134,071)
Proceeds from investment securities available for sale	662,496	227,920
Proceeds from investment securities held to maturity	282	278
Proceeds from sale of equity securities	81,853	0
Purchases of restricted equity securities	(205,400)	(45,600)
Redemption of restricted equity securities	202,605	46,788
Net change in loans and leases	(619,257)	(687,453)
Proceeds from sales of loans and leases	58,478	41,613
Change in premises and equipment	(5,387)	(2,820)
Proceeds from bank owned life insurance death benefits	1,869	1,481
Proceeds from sales of other real estate owned	856	1,629
Net cash paid in store divestiture	(44,646)	0
Net cash used in investing activities	(188,661)	(550,235)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposit liabilities	731,192	796,618
Net increase (decrease) in securities sold under agreements to repurchase	10,901	(20,633)
Proceeds from term debt borrowings	330,670	50,000
Repayment of term debt borrowings	(260,670)	(50,652)
Repayment of junior subordinated debentures at amortized cost	0	(10,598)
Dividends paid on common stock	(92,551)	(83,650)
Proceeds from stock options exercised	21	1,016
Repurchase and retirement of common stock	(1,980)	(12,507)
Net cash provided by financing activities	717,583	669,594
Net increase in cash and cash equivalents	411,154	168,732
Cash and cash equivalents, beginning of period	622,637	634,280
Cash and cash equivalents, end of period	1,033,791	803,012
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	96,766	51,048
Income taxes	58,827	38,029
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized gains on investment securities available for sale, net of taxes	60,326	(34,428)
Change in unrealized gains on junior subordinated debentures carried at fair value, net of taxes	17,701	(2,380)
Junior subordinated debentures, at fair value, cumulative effect adjustment	0	9,710
Cash dividend declared on common stock and payable after period-end	46,305	44,012
Change in GNMA mortgage loans recognized due to repurchase option	(3,470)	(3,223)
Transfer of loans to other real estate owned	$ 948	$ 1,866