Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
FDIC loss-sharing agreement early termination, pretax loss	$ 2,409	$ 0
Cash Flows From Operating Activities
Net income	97,100	74,148
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan and lease losses	5,304	10,760
Stock-based compensation expense	5,915	3,626
Depreciation, amortization and accretion	21,483	27,796
Investment securities gains	0	1,174
Net realized (gain) loss on sale of premises and equipment, loans held for investment and other assets	(189)	186
Net realized loss on sale and valuation adjustments of other real estate owned	489	101
Originations of loans held for sale	99,130	76,645
Proceeds from sales of loans held for sale	97,174	77,793
Net change in:
Interest receivable	(6,089)	(3,729)
Interest payable	(21)	(84)
Other assets	3,359	(7,714)
Other liabilities	(2,624)	13,416
Net cash provided by operating activities	111,180	118,480
Gain on sale of merchant card services portfolio	(14,000)	0
Cash Flows From Investing Activities
Loans originated and acquired, net of principal collected	(304,831)	(450,914)
Purchases of securities available for sale	(130,906)	(502,602)
Purchases of premises and equipment	(4,380)	(2,705)
Payments to Acquire Federal Home Loan Bank Stock	(92,040)	(57,799)
Proceeds from FDIC for reimbursement on loss-sharing asset	26	878
Proceeds from sales of securities available for sale	0	120,800
Proceeds from principal repayments and maturities of securities available for sale	200,470	199,677
Proceeds from Sales of Assets, Investing Activities	12,157	7,391
Proceeds from sale of merchant card services portfolio	14,000	0
Proceeds from Sale of Federal Home Loan Bank Stock	92,040	57,881
Proceeds from sales of other real estate and other personal property owned	1,901	5,845
Payment to FDIC to terminate loss-sharing agreements	4,666	0
Payments to FDIC related to loss-sharing asset	(210)	(855)
Net cash used in investing activities	(216,439)	(622,403)
Cash Flows From Financing Activities
Net increase in deposits	282,336	619,162
Net decrease in sweep repurchase agreements	(39,889)	(30,510)
Proceeds from Federal Home Loan Bank advances	2,301,000	1,347,000
Federal Reserve Bank borrowings	10	10
Proceeds from exercise of stock options	1,980	1,304
Repayment of Federal Home Loan Bank advances	(2,301,000)	(1,349,000)
Repayment of Federal Reserve Bank borrowings	10	10
Payment of common stock dividends	(38,466)	(66,041)
Preferred stock dividends	0	(117)
Purchase and retirement of common stock	2,246	1,113
Net cash provided by financing activities	203,715	520,685
Increase in cash and cash equivalents	98,456	16,762
Cash and cash equivalents at beginning of period	224,238	175,302
Cash and cash equivalents at end of period	322,694	192,064
Supplemental Information:
Cash paid for interest	4,161	3,437
Cash paid for income tax	37,701	20,825
Non-cash investing and financing activities
Loans transferred to other real estate owned	$ 74	$ 1,202