Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 44,367	$ 42,326
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,527	8,939
Provision for loan losses	1,488	2,454
Deferred income taxes	1,998	3,993
Gain on sale of securities, net	(541)
Share-based compensation expense	2,131	1,993
Accretion of discount related to performing acquired loans	(3,170)	(9,656)
(Gain) loss on disposal of premises and equipment	271	(72)
Gain on sale of OREO	(2)	(58)
Net amortization of premiums on investment securities	1,699	1,966
OREO write downs	98	777
Fair value adjustment for loans held for sale	(156)	(215)
Originations and purchases of loans held for sale	(127,166)	(154,234)
Proceeds from sales of loans	116,951	182,649
Net change in:
Accrued interest receivable	(968)	1,553
Prepaid assets	(2,061)	(526)
Operating Leases	256
Miscellaneous other assets	(13,306)	14,251
Accrued interest payable	969	775
Accrued income taxes	9,231	6,984
Miscellaneous other liabilities	(3,102)	1,846
Net cash provided by operating activities	37,514	105,745
Cash flows from investing activities:
Proceeds from sales of investment securities available for sale	134,486	5,215
Proceeds from maturities and calls of investment securities held to maturity		1,255
Proceeds from maturities and calls of investment securities available for sale	55,242	57,972
Proceeds from sales of other investment securities	45	2,125
Purchases of investment securities available for sale	(122,774)	(79,661)
Purchases of other investment securities	(15,066)	(2,556)
Net increase in loans	(127,840)	(10,461)
Net cash received from acquisitions		6
Recoveries of loans previously charged off	958	966
Purchases of premises and equipment	(3,436)	(3,615)
Proceeds from sale of OREO	1,019	2,516
Proceeds from sale of premises and equipment	6	6
Net cash used in investing activities	(77,360)	(26,232)
Cash flows from financing activities:
Net increase in deposits	272,038	130,332
Net increase in federal funds purchased and securities sold under agreements to repurchase and other short-term borrowings	6,242	70,717
Proceeds from FHLB advances	500,000	50,000
Repayment of other borrowings	(150,002)	(50,001)
Common stock repurchase	(34,785)	(1,612)
Dividends paid on common stock	(13,441)	(12,138)
Stock options exercised	402	66
Net cash provided by financing activities	580,454	187,364
Net increase in cash and cash equivalents	540,608	266,877
Cash and cash equivalents at beginning of period	408,983	377,627
Cash and cash equivalents at end of period	949,591	644,504
Cash paid for:
Interest	19,154	8,300
Income taxes	874	786
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	1,956
Acquisitions:
Fair value of tangible assets acquired		(5)
Net identifiable assets acquired over liabilities assumed		(5)
Real estate acquired in full or in partial settlement of loans	$ 1,004	$ 2,895