Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities
Net income	$ 128,134	$ 97,100
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan and lease losses	12,980	5,304
Stock-based compensation expense	6,231	5,915
Depreciation, amortization and accretion	25,807	21,483
Investment securities losses, net	(73)	0
Net realized (gain) loss on sale of premises and equipment, loans held for investment and other assets	(142)	189
Net realized loss on sale and valuation adjustments of other real estate owned	(1,299)	(489)
Gain on sale of merchant card services portfolio	0	14,000
Gain on bank owned life insurance death benefit	0	2,980
FDIC loss-sharing agreement early termination, pretax charge	0	2,409
Originations of loans held for sale	103,614	99,130
Proceeds from sales of loans held for sale	104,105	97,174
Net change in:
Interest receivable	(7,595)	(6,089)
Interest payable	618	(21)
Other assets	(2,599)	(4,406)
Other liabilities	5,662	(2,624)
Net cash provided by operating activities	171,243	100,435
Cash Flows From Investing Activities
Loans originated, net of principal collected	(168,382)	(304,831)
Purchases of securities available for sale	(606,052)	(130,906)
Purchases of premises and equipment	(8,253)	(4,380)
Payments to Acquire Federal Home Loan Bank Stock	(136,120)	(92,040)
Proceeds from FDIC for reimbursement on loss-sharing asset	0	26
Proceeds from sales of securities available for sale	32,330	0
Proceeds from principal repayments and maturities of securities available for sale	311,956	200,470
Proceeds from Sales of Assets, Investing Activities	14,956	12,157
Proceeds from sale of merchant card services portfolio	0	14,000
Proceeds from Sale of Federal Home Loan Bank Stock	129,920	92,040
Proceeds from sales of other real estate and other personal property owned	5,868	1,901
Proceeds from Life Insurance Policy	5,074	10,745
Payment from (to) FDIC to terminate loss-sharing agreements	0	(4,666)
Payments to FDIC related to loss-sharing asset	0	(210)
Net cash used in investing activities	(418,703)	(205,694)
Cash Flows From Financing Activities
Net increase in deposits	72,151	282,336
Net decrease in sweep repurchase agreements	(16,862)	(39,889)
Proceeds from Federal Home Loan Bank advances	3,403,000	2,301,000
Federal Reserve Bank borrowings	5,010	10
Proceeds from exercise of stock options	1,857	1,980
Repayment of Federal Home Loan Bank advances	(3,248,000)	(2,301,000)
Repayment of Federal Reserve Bank borrowings	5,010	10
Payment of common stock dividends	(54,149)	(38,466)
Repayments of junior subordinated debt	8,248	0
Purchase and retirement of common stock	2,660	2,246
Net cash provided by financing activities	147,089	203,715
Increase (decrease) in cash and cash equivalents	(100,371)	98,456
Cash and cash equivalents at beginning of period	342,533	224,238
Cash and cash equivalents at end of period	242,162	322,694
Supplemental Information:
Cash paid for interest	11,699	4,161
Cash paid for income tax	12,768	37,701
Non-cash investing and financing activities
Loans transferred to other real estate owned	1,200	74
Premises and equipment expenditures incurred but not yet paid	464	0
Change in dividends payable on unvested shares	$ 6	$ 0