Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
FDIC loss-sharing agreement early termination, pretax loss	$ 2,409	$ 0
Cash Flows From Operating Activities
Net income	56,331	46,664
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan and lease losses	5,952	8,894
Stock-based compensation expense	4,114	2,551
Depreciation, amortization and accretion	13,968	18,898
Investment securities gains	0	602
Net realized (gain) loss on sale of premises and equipment, loans held for investment and other assets	(176)	170
Net realized loss on sale and valuation adjustments of other real estate owned	(221)	(160)
Originations of loans held for sale	65,902	46,705
Proceeds from sales of loans held for sale	64,830	43,565
Net change in:
Interest receivable	(782)	(1,861)
Interest payable	35	(74)
Other assets	(5,987)	(7,818)
Other liabilities	(9,230)	9,809
Net cash provided by operating activities	65,783	73,651
Cash Flows From Investing Activities
Loans originated and acquired, net of principal collected	(216,541)	(298,259)
Purchases of securities available for sale	(114,309)	(296,920)
Purchases of premises and equipment	(1,947)	(1,199)
Payments to Acquire Federal Home Loan Bank Stock	(86,840)	(42,400)
Proceeds from FDIC for reimbursement on loss-sharing asset	26	668
Proceeds from sales of securities available for sale	0	83,410
Proceeds from principal repayments and maturities of securities available for sale	131,472	123,817
Proceeds from Sales of Assets, Investing Activities	8,133	4,631
Proceeds from Sale of Federal Home Loan Bank Stock	80,720	36,961
Proceeds from sales of other real estate and other personal property owned	1,719	3,276
Payment to FDIC to terminate loss-sharing agreements	(4,666)	0
Payments to FDIC related to loss-sharing asset	(210)	(625)
Net cash used in investing activities	(202,443)	(386,640)
Cash Flows From Financing Activities
Net increase in deposits	13,078	234,526
Net decrease in sweep repurchase agreements	(14,927)	(10,481)
Proceeds from Federal Home Loan Bank advances	2,171,000	962,000
Federal Reserve Bank borrowings	10	10
Proceeds from exercise of stock options	1,155	603
Repayment of Federal Home Loan Bank advances	(2,018,000)	(826,000)
Repayment of Federal Reserve Bank borrowings	10	10
Payment of common stock dividends	(25,621)	(43,404)
Preferred stock dividends	0	(77)
Purchase and retirement of common stock	2,215	1,092
Net cash provided by financing activities	124,470	316,075
Increase (decrease) in cash and cash equivalents	(12,190)	3,086
Cash and cash equivalents at beginning of period	224,238	175,302
Cash and cash equivalents at end of period	212,048	178,388
Supplemental Information:
Cash paid for interest	2,731	2,241
Cash paid for income tax	22,881	11,130
Non-cash investing and financing activities
Loans transferred to other real estate owned	$ 0	$ 311