Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Cash Flows From Operating Activities
Net income	$ 20,673	$ 7,555
Reconciliation of net income to net cash provided by operating activities:
Provision (reversal) for loan losses	(3,659)	723	$ 723
Net security premium amortization	685	232
Loan discount accretion	(2,111)	(1,360)
Purchase accounting accretion and amortization, net	(71)	(48)
Foreclosed property (gains) losses and write-downs, net	288	(25)
Loss (gain) on securities available for sale		235
Other losses (gains)	(4)	(234)
Decrease (increase) in net deferred loan fees	(786)	655
Depreciation of premises and equipment	1,445	1,300
Stock-based compensation expense	231	178
Amortization of intangible assets	1,672	576
Fees/gains from sale of presold mortgages and SBA loans	(4,661)	(1,390)
Origination of presold mortgages in process of settlement	(33,834)	(39,061)
Proceeds from sales of presold mortgages in process of settlement	40,945	37,493
Origination of SBA loans for sale	(63,040)	(9,779)
Proceeds from sales of SBA loans	50,996	7,961
Decrease in accrued interest receivable	824	279
Decrease in other assets	2,030	3,741
Increase (decrease) in accrued interest payable	71	(112)
Decrease in other liabilities	(6,279)	(8,257)
Net cash provided by operating activities	5,415	662
Cash Flows From Investing Activities
Purchases of securities available for sale	(13,182)	(29,313)
Proceeds from maturities/issuer calls of securities available for sale	7,764	6,632
Proceeds from maturities/issuer calls of securities held to maturity	6,159	7,357
Proceeds from sales of securities available for sale		46,618
Purchases of Federal Reserve and Federal Home Loan Bank stock, net	(6,099)	(3,766)
Net increase in loans	(49,662)	(81,048)
Proceeds from sales of foreclosed real estate	1,455	1,818
Purchases of premises and equipment	(1,224)	(873)
Proceeds from sales of premises and equipment	540
Net cash received in acquisition		56,185
Net cash provided (used) by investing activities	(54,249)	3,610
Cash Flows From Financing Activities
Net increase in deposits	88,869	96,519
Net decrease in borrowings	(529)
Cash dividends paid - common stock	(2,372)	(1,669)
Proceeds from stock option exercises	108	45
Net cash provided by financing activities	86,076	94,895
Increase in cash and cash equivalents	37,242	99,167
Cash and cash equivalents, beginning of period	489,490	305,993	305,993
Cash and cash equivalents, end of period	526,732	405,160	$ 489,490
Supplemental Disclosures of Cash Flow Information:
Cash paid during the period for: interest	4,483	2,020
Cash paid during the period for: income taxes	(181)	(1,495)
Non-cash transactions:
Unrealized gain (loss) on securities available for sale, net of taxes	(5,587)	854
Foreclosed loans transferred to other real estate	$ 648	$ 1,968