Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities:
Net income	$ 123,275	$ 99,152
Adjustments to reconcile net income to net cash provided by (used for) operating activities
Provision for credit losses	14,100	17,163
Depreciation, amortization and accretion, net	29,958	27,296
Stock-based compensation expense	5,746	4,752
Net amortization of premium on securities	3,198	1,840
Accretion of discount on loans	(11,979)	(15,849)
Mortgage servicing rights fair value change, net	(1,265)	(4,291)
Originations and purchases of mortgage loans held-for-sale	(1,856,725)	(1,948,890)
Proceeds from sales of mortgage loans held-for-sale	1,928,870	1,825,686
Bank owned life insurance (BOLI) income	(1,873)	(1,729)
Decrease (increase) in trading securities, net	2	(3,165)
Net decrease in brokerage customer receivables	1,900	765
Gains on mortgage loans sold	(43,547)	(43,014)
Losses (gains) on investment securities, net	8	(2,765)
Gains on early extinguishment of debt	0	(4,305)
(Gains) losses on sales of premises and equipment, net	(140)	3
Net losses on sales and fair value adjustments of other real estate owned	896	322
Increase in accrued interest receivable and other assets, net	(45,232)	(116,118)
(Decrease) increase in accrued interest payable and other liabilities, net	(22,451)	70,756
Net Cash Provided by (Used for) Operating Activities	124,741	(92,391)
Investing Activities:
Proceeds from maturities of available-for-sale securities	138,516	529,463
Proceeds from maturities of held-to-maturity securities	50,923	319
Proceeds from sales and calls of available-for-sale securities	9,729	1,071,996
Proceeds from calls of held-to-maturity securities	51,062	281,981
Purchases of available-for-sale securities	(185,245)	(1,526,467)
Purchases of held-to-maturity securities	(256,532)	(350,078)
Redemption (purchase) of Federal Home Loan Bank and Federal Reserve Bank stock, net	52,682	(19,738)
Net cash paid in business combinations	(284)	(18,133)
Proceeds from sales of other real estate owned	8,601	19,455
Proceeds received from the FDIC related to reimbursements on covered assets	791	420
Net increase in interest bearing deposits with banks	(31,178)	(81,250)
Net increase in loans	(1,032,772)	(942,958)
Redemption of BOLI	0	659
Purchases of premises and equipment, net	(26,260)	(24,235)
Net Cash Used for Investing Activities	(1,219,967)	(1,058,566)
Financing Activities:
Increase in deposit accounts	947,150	1,302,188
Increase (decrease) in subordinated notes and other borrowings, net	15,163	(13,249)
Increase (decrease) in Federal Home Loan Bank advances, net	163,000	(271,025)
Proceeds from the issuance of common stock, net	0	152,823
Redemption of junior subordinated debentures, net	0	(10,695)
Issuance of common shares resulting from the exercise of stock options, employee stock purchase plan and conversion of common stock warrants	17,120	5,766
Common stock repurchases for tax withholdings related to stock-based compensation	(295)	(172)
Dividends paid	(20,796)	(18,899)
Net Cash Provided by Financing Activities	1,121,342	1,146,737
Net Increase (Decrease) in Cash and Cash Equivalents	26,116	(4,220)
Cash and Cash Equivalents at Beginning of Period	270,045	275,795
Cash and Cash Equivalents at End of Period	$ 296,161	$ 271,575