Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 137,392	$ 129,867
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,981	26,864
Provision for loan losses	9,220	10,049
Deferred income taxes	1,457	9,897
Revision of provisional amount related to the revaluation of deferred taxes from the Tax Reform Act		(991)
(Gains) losses on sale of securities, net	(2,687)	652
Share-based compensation expense	6,642	6,613
Accretion of discount related to performing acquired loans	(9,131)	(23,993)
Loss on disposal of premises and equipment	3,648	1,304
Gain on sale of OREO	(527)	(1,570)
Net amortization of premiums on investment securities	5,310	5,696
OREO write downs	727	1,185
Fair value adjustment for loans held for sale	1,463	(699)
Originations and purchases of loans held for sale	(591,590)	(491,694)
Proceeds from sales of loans	525,659	529,528
Net change in:
Accrued interest receivable	(134)	(2,081)
Prepaid assets	(846)	1,833
Operating Leases	1,134
Miscellaneous other assets	(49,803)	(1,706)
Accrued interest payable	317	1,490
Accrued income taxes	2,625	649
Miscellaneous other liabilities	63,173	20,890
Net cash provided by operating activities	129,030	223,783
Cash flows from investing activities:
Proceeds from sales of investment securities available for sale	231,990	67,853
Proceeds from maturities and calls of investment securities held to maturity		2,030
Proceeds from maturities and calls of investment securities available for sale	208,640	173,531
Proceeds from sales of other investment securities	45	15,938
Purchases of investment securities available for sale	(692,114)	(191,305)
Purchases of other investment securities	(23,566)	(12,119)
Net increase in loans	(280,684)	(283,331)
Recoveries of loans previously charged off	2,833	2,686
Purchases of premises and equipment	(11,533)	(9,504)
Proceeds from sale of OREO	7,405	11,655
Proceeds from sale of premises and equipment	17	33
Net cash used in investing activities	(556,967)	(222,533)
Cash flows from financing activities:
Net increase in deposits	376,854	81,721
Net decrease in federal funds purchased and securities sold under agreements to repurchase and other short-term borrowings	(1,577)	(7,159)
Proceeds from FHLB advances	700,001	325,001
Repayment of other borrowings	(150,005)	(425,005)
Common stock issuance	717	709
Common stock repurchases	(146,897)	(10,360)
Dividends paid on common stock	(42,175)	(37,506)
Stock options exercised	1,230	1,031
Net cash provided by (used in) financing activities	738,148	(71,568)
Net increase (decrease) in cash and cash equivalents	310,211	(70,318)
Cash and cash equivalents at beginning of period	408,983	377,627
Cash and cash equivalents at end of period	719,194	307,309
Cash paid for:
Interest	65,237	35,026
Income taxes	31,928	23,981
Initial measurement and recognition of operating lease assets in exchange for lease liabilities per ASU 2016-02	82,160
Recognition of operating lease assets in exchange for lease liabilities	10,239
Acquisitions:
Fair value of tangible assets acquired		(7,246)
Other intangible assets acquired		3,321
Liabilities assumed		(612)
Net identifiable assets acquired over liabilities assumed		(3,313)
Real estate acquired in full or in partial settlement of loans	$ 9,610	$ 11,976