CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 431,677	$ 384,677	$ 345,878
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	162,596	107,397	117,485
Accretion of discount and amortization of premiums, net	(51,042)	(63,770)	(184,318)
Changes in FDIC indemnification asset and receivable/payable	0	37,980	201,417
Stock compensation costs	22,102	16,502	13,883
Deferred tax expenses (benefit)	26,966	261,214	(147,868)
Provision for credit losses	27,479	14,217	49,158
Net gains on sales of loans	(6,087)	(24,874)	(39,132)
Net gains on sales of available-for-sale investment securities	(10,362)	(40,367)	(10,715)
Net gains on sales of premises and equipment and OREO	(4,129)	(14,646)	(14,056)
Originations and purchases of loans held-for-sale	(18,804)	(623)	(92,475)
Proceeds from sales and paydowns/payoffs in loans held-for-sale	23,749	3,174	288,706
Repurchase agreements’ extinguishment costs	0	21,818	0
Net payments to FDIC shared-loss agreements	0	(132,999)	(1,343)
Net change in accrued interest receivable and other assets	24,837	(113,457)	(89,036)
Net change in accrued expenses and other liabilities	15,353	16,785	(38,586)
Other net operating activities	(2,479)	(3,404)	(6,100)
Total adjustments	210,179	84,947	47,020
Net cash provided by operating activities	641,856	469,624	392,898
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisitions, net of cash paid	0	0	138,465
Net (increase) decrease in:
Loans held-for-investment	(1,549,736)	(3,285,436)	(2,552,244)
Interest-bearing deposits with banks	(38,249)	30,140	(81,241)
Investments in qualified affordable housing partnerships, tax credit and other investments	(87,860)	(95,074)	(87,925)
Purchases of:
Resale agreements	(1,550,000)	(1,675,000)	(925,000)
Available-for-sale investment securities	(2,396,199)	(3,547,193)	(960,135)
Loans held-for-investment	(1,142,054)	(282,548)	(865,267)
Proceeds from sale of:
Available-for-sale investment securities	1,275,645	1,669,334	623,689
Loans held-for-investment	661,025	1,729,187	856,434
OREO	7,408	41,050	70,936
Paydowns and maturities of resale agreements	1,500,000	1,050,000	800,000
Repayments, maturities and redemptions of available-for-sale investment securities	1,503,127	734,934	554,742
Other net investing activities	24,233	2,725	67,653
Net cash used in investing activities	(1,792,660)	(3,627,881)	(2,359,893)
Net increase in:
Deposits	2,452,870	3,492,603	2,277,007
Short-term borrowings	62,506	0	0
Proceeds from:
FHLB advances	0	700,000	0
Issuance of common stock pursuant to various stock compensation plans and agreements	2,982	2,835	6,794
Payments for:
Repayment of FHLB advances	(700,000)	0	(10,000)
Repayment of long-term debt	(20,000)	(20,000)	(30,310)
Extinguishment of repurchase agreements	0	(566,818)	(25,000)
Repurchase of vested shares due to employee tax liability	(3,225)	(5,964)	(10,326)
Cash dividends on common stocks	(115,828)	(115,641)	(103,618)
Other net financing activities	1,055	3,291	6,513
Net cash provided by financing activities	1,680,360	3,490,306	2,111,060
Effect of exchange rate changes on cash and cash equivalents	(11,940)	(11,047)	0
NET INCREASE IN CASH AND CASH EQUIVALENTS	517,616	321,002	144,065
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	1,360,887	1,039,885	895,820
CASH AND CASH EQUIVALENTS, END OF YEAR	1,878,503	1,360,887	1,039,885
Cash paid (received) during the year for:
Interest	104,251	105,831	112,695
Income tax payments (refunds), net	39,478	(18,601)	321,177
Noncash investing and financing activities:
Loans held-for-investment transferred to loans held-for-sale, net	814,157	1,694,245	837,389
Transfers to OREO	8,083	9,296	47,547
Loans to facilitate sale of OREO	0	1,750	2,000
Held-to-maturity investment security retained from securitization of loans	160,135	0	0
Dividends payable	767	583	397
Issuance of common stock related to acquisition	$ 0	$ 0	$ 190,830