CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 60,100	$ 40,103	$ 25,515
Adjustments to net income:
Depreciation and amortization expense	4,888	2,854	2,432
Provision for loan losses	8,640	8,776	6,425
Share-based compensation expense	5,809	2,729	1,165
Loss on sale and disposal of premises and equipment	234	656	0
(Gain) loss on sale of or write down of other real estate owned	(46)	321	92
Net amortization on securities available-for-sale	7,601	9,157	3,822
Net accretion of discounts/premiums for loans acquired and deferred loan fees/costs	1,627	1,832	(2,967)
Gain on sale of investment securities available-for-sale	(2,737)	(1,797)	(290)
Other-than-temporary impairment recovery on investment securities, net	0	(205)	0
Originations of loans held for sale	(142,104)	(103,883)	(87,900)
Proceeds from the sales of and principal payments from loans held for sale	140,012	115,877	86,604
Gain on sale of loans	(12,468)	(9,539)	(7,970)
Deferred income tax expense (benefit)	16,866	3,887	(1,395)
Change in accrued expenses and other liabilities, net	5,003	(4,428)	6,786
Income from bank owned life insurance, net	(1,842)	(1,164)	(1,147)
Amortization of core deposit intangible	6,144	2,039	1,350
Change in accrued interest receivable and other assets, net	(13,728)	(3,768)	(8,853)
Net cash (used in) provided by operating activities	83,999	63,447	23,669
Cash flows from investing activities:
Net increase in interest-bearing time deposits with financial institutions	251	0	(1,972)
Increase in loans, net	(519,407)	(263,075)	(247,000)
Purchase of loans held for investment	(13,582)	(271,159)	(43,440)
Change in other real estate owned from sales	507	380	(216)
Purchase of held-to-maturity securities	0	0	(9,642)
Principal payments on securities available-for-sale	76,057	38,935	33,751
Purchase of securities available-for-sale	(317,441)	(190,140)	(90,127)
Proceeds from sale of securities available-for-sale	268,596	230,945	27,642
Proceeds from the sale of premises and equipment	0	10,049	1,506
Investment in bank owned life insurance	198	0	0
Purchases of premises and equipment	(4,165)	(11,970)	(1,887)
Change in FHLB, FRB, and other stock, at cost	(12,838)	(15,012)	(2,856)
Cash acquired in acquisitions	225,945	40,132	2,961
Net cash used in investing activities	(295,879)	(430,915)	(331,280)
Cash flows from financing activities:
Net increase in deposit accounts	187,883	313,770	228,279
Net change in federal funds purchased	0	0	(1,500)
Net change in short-term borrowings	61,120	181,846	47,682
Proceeds from long-term borrowings	12,012	0	0
Repayment of long-term borrowings	(9,262)	(50,927)	0
Proceeds from exercise of stock options and warrants	4,592	1,345	758
Repurchase of common stock	(1,258)	(126)	(116)
Net cash provided by financing activities	255,087	445,908	275,103
Net increase (decrease) in cash and cash equivalents	43,207	78,440	(32,508)
Cash and cash equivalents, beginning of year	156,857	78,417	110,925
Cash and cash equivalents, end of year	200,064	156,857	78,417
Supplemental cash flow disclosures:
Interest paid	21,777	13,564	12,081
Income taxes paid	18,846	13,139	12,127
NONCASH INVESTING ACTIVITIES DURING THE PERIOD
Transfers from loans to other real estate owned	121	197	450
Assets acquired (liabilities assumed) in acquisitions (See Note 25):
Interest-bearing deposits with financial institutions	0	1,972	0
Investment securities	442,923	190,254	56,121
Loans	2,427,589	456,158	332,893
Core deposit intangible	39,703	4,319	2,903
Deferred income tax	14,959	6,748	4,794
Bank owned life insurance	0	0	11,276
Goodwill	391,070	51,658	27,882
Fixed assets	42,097	4,190	2,134
Other assets	74,379	9,362	2,402
Deposits	(2,752,501)	(636,591)	(336,018)
Other borrowings	(180,186)	0	(33,300)
Other liabilities	(16,395)	(8,843)	(1,796)
Common Stock and additional paid-in capital	$ (716,421)	$ (120,174)	$ (79,777)