Consolidated Statement of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income		$ 505,624	$ 431,677	$ 384,677
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		149,822	137,578	88,728
Accretion of discount and amortization of premiums, net		(7,260)	(26,024)	(45,101)
Changes in FDIC indemnification asset and receivable/payable		0	0	37,980
Stock compensation costs		24,657	22,102	16,502
Deferred income tax expense		33,856	26,966	261,214
Provision for credit losses		46,266	27,479	14,217
Net gains on sales of loans		(8,870)	(6,085)	(24,873)
Net gains on sales of available-for-sale investment securities		(8,037)	(10,362)	(40,367)
Net gains on sales of premises and equipment		(77,388)	(3,178)	(3,567)
Net gains on sales of OREO		(1,024)	(951)	(11,079)
Net gain on sale of business		(3,807)	0	0
Originations and purchases of loans held-for-sale		(20,521)	(18,804)	(623)
Proceeds from sales and paydowns/payoffs in loans held-for-sale		21,363	23,749	3,174
Repurchase agreements’ extinguishment costs		0	0	21,818
Net payments to FDIC shared-loss agreements		0	0	(132,999)
Net change in accrued interest receivable and other assets		46,005	23,685	(117,046)
Net change in accrued expenses and other liabilities		(1,966)	15,353	16,785
Other net operating activities		(1,814)	(1,329)	184
Total adjustments		191,282	210,179	84,947
Net cash provided by (used in) operating activities		696,906	641,856	469,624
Net (increase) decrease in:
Loans held-for-investment		(3,514,786)	(1,549,736)	(3,285,436)
Interest-bearing deposits with banks		(63,096)	(38,249)	30,140
Investments in qualified affordable housing partnerships, tax credit and other investments		(161,661)	(87,860)	(95,074)
Purchases of:
Resale agreements		(600,000)	(1,550,000)	(1,675,000)
Available-for-sale investment securities		(828,604)	(2,396,199)	(3,547,193)
Loans held-for-investment		(534,816)	(1,142,054)	(282,548)
Premises and equipment		(13,754)	(12,181)	(6,555)
Proceeds from sale of:
Available-for-sale investment securities		832,844	1,275,645	1,669,334
Loans held-for-investment		566,688	661,025	1,729,187
Other real estate owned (“OREO”)		6,999	7,408	41,050
Premises and equipment		119,749	8,163	7,133
Business, net of cash transferred		3,633	0	0
Paydowns and maturities of resale agreements		1,250,000	1,500,000	1,050,000
Repayments, maturities and redemptions of available-for-sale investment securities		413,593	1,503,127	734,934
Other net investing activities		22,756	28,251	2,147
Net cash used in investing activities		(2,500,455)	(1,792,660)	(3,627,881)
Net increase (decrease) in:
Deposits		2,272,500	2,452,870	3,492,603
Short-term borrowings		(61,560)	62,506	0
Proceeds from:
FHLB advances		0	0	700,000
Issuance of common stock pursuant to various stock compensation plans and agreements		2,280	2,982	2,835
Payments for:
Repayment of FHLB advances		0	(700,000)	0
Repayment of long-term debt		(15,000)	(20,000)	(20,000)
Extinguishment of repurchase agreements		0	0	(566,818)
Repurchase of vested shares due to employee tax liability		(12,940)	(3,225)	(5,964)
Cash dividends on common stock		(116,820)	(115,828)	(115,641)
Other net financing activities		0	1,055	3,291
Net cash provided by financing activities		2,068,460	1,680,360	3,490,306
Effect of exchange rate changes on cash and cash equivalents		31,178	(11,940)	(11,047)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS		296,089	517,616	321,002
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		1,878,503	1,360,887	1,039,885
CASH AND CASH EQUIVALENTS, END OF YEAR		2,174,592	1,878,503	1,360,887
Cash paid (received) during the year for:
Interest paid		138,766	104,251	105,831
Income taxes paid (refunded), net		98,126	39,478	(18,601)
Noncash investing and financing activities:
Loans transferred from held-for-investment to held-for-sale	[1]	613,088	819,100	1,747,621
Loans transferred from held-for-sale to held-for-investment		0	(4,943)	(53,376)
Deposits transferred to branch liability held-for-sale		605,111	0	0
Investment security transferred from held-to-maturity to available-for-sale		115,615	0	0
Held-to-maturity investment security retained from securitization of loans		0	160,135	0
Premises and equipment transferred to branch assets held-for-sale		8,043	0	0
Loans transferred to OREO		$ 777	$ 8,083	$ 9,296

[1] December 31, 2017 amount includes loans transferred from held-for-investment to branch assets held-for-sale.