Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 164,148	$ 163,665
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of investment premiums, net	22,526	16,401
Gain on sale of investment securities, net	(27)	(858)
Gain on sale of other real estate owned, net	(620)	(1,683)
Valuation adjustment on other real estate owned	146	1,601
Provision for loan and lease losses	34,326	28,503
Change in cash surrender value of bank owned life insurance	(6,272)	(6,483)
Depreciation, amortization and accretion	43,628	44,607
Loss on sale of premises and equipment	1,127	5,221
Additions to residential mortgage servicing rights carried at fair value	(23,486)	(25,020)
Change in fair value of residential mortgage servicing rights carried at fair value	25,234	42,391
Change in junior subordinated debentures carried at fair value	4,666	4,657
Stock-based compensation	6,688	7,523
Net increase in trading account assets	(955)	(1,280)
Gain on sale of loans, net	(103,665)	(136,949)
Change in loans held for sale carried at fair value	(7,210)	(13,555)
Origination of loans held for sale	(2,563,978)	(2,928,951)
Proceeds from sales of loans held for sale	2,631,668	3,133,551
Goodwill impairment	0	142
Change in other assets and liabilities:
Net decrease in other assets	21,390	9,336
Net (decrease) increase in other liabilities	(2,282)	44,314
Net cash provided by operating activities	247,052	387,133
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(783,430)	(443,094)
Proceeds from investment securities available for sale	437,007	461,342
Proceeds from investment securities held to maturity	392	389
Purchases of restricted equity securities	(243,171)	(600)
Redemption of restricted equity securities	243,190	12
Net change in loans and leases	(1,405,145)	(1,248,475)
Proceeds from sales of loans	218,944	429,997
Net change in premises and equipment	(14,131)	(22,573)
Proceeds from bank owned life insurance death benefits	373	814
Proceeds from sales of other real estate owned	5,825	13,608
Net cash used in investing activities	(1,540,146)	(808,580)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposit liabilities	831,811	1,213,354
Net (decrease) increase in securities sold under agreements to repurchase	(31,406)	4,903
Proceeds from term debt borrowings	205,000	490,000
Repayment of term debt borrowings	(205,000)	(475,014)
Dividends paid on common stock	(105,748)	(105,824)
Proceeds from stock options exercised	548	1,098
Repurchase and retirement of common stock	(5,977)	(14,354)
Net cash provided by financing activities	689,228	1,114,163
Net (decrease) increase in cash and cash equivalents	(603,866)	692,716
Cash and cash equivalents, beginning of period	1,449,432	773,725
Cash and cash equivalents, end of period	845,566	1,466,441
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	58,191	53,783
Income taxes	25,668	12,921
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized gains on investment securities available for sale, net of taxes	13,819	19,230
Cash dividend declared on common stock and payable after period-end	39,649	35,250
Transfer of loans to loans held for sale	0	265,741
Change in GNMA mortgage loans recognized due to repurchase option	1,445	(11,857)
Transfer of loans to other real estate owned	2,851	5,409
Transfers from other real estate owned to loans due to internal financing	$ 78	$ 5,881