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	$ 20,649	$ 9,374	$ 10,300
Adjustments to reconcile net income to net cash from operating activities:
Stock based compensation	1,100	553	531
Depreciation	2,496	1,764	1,672
Provision for loan losses	2,953	2,119	3,047
Net amortization (accretion) of purchase valuation adjustments	(4,518)	615	(380)
Amortization (accretion) of premiums and discounts on securities	2,869	3,049	2,309
Amortization of intangible assets	1,070	419	275
Deferred income taxes	2,621	909	2,427
Federal Home Loan Bank stock dividends	(760)	(657)	(407)
Loss (gain) on sales and valuation adjustments on other real estate owned	(109)	(112)	(44)
Net loss (gain) on sales and settlements of securities	(271)	(479)	(756)
Loss (gain) on disposal of premises and equipment	(5)	(42)	11
Loss (gain) on sales of foreclosed assets	32
Loss (gain) on sales of loans	(1,640)	(1,198)	(903)
Originations of loans held for sale	(96,400)	(51,369)	(41,407)
Proceeds from the sale of loans held for sale	100,026	51,241	39,703
Increase in the value of bank-owned life insurance	(1,445)	(1,000)	(957)
Change in fair value of derivatives recognized in earnings	(14)	6	13
Gain on acquisition			(682)
Net change in:
Interest receivable	(1,276)	(544)	(751)
Other assets	(673)	885	(2,551)
Interest payable and other liabilities	433	15	2,170
Net cash provided by operating activities	27,138	15,548	13,620
Cash flows (to) from investing activities
Purchases of available-for-sale securities	(105,749)	(56,391)	(108,997)
Purchases of held-to-maturity securities	(129,016)	(134,745)	(97,103)
Proceeds from sales, calls, pay-downs, and maturities of available-for-sale securities	102,040	90,459	60,088
Proceeds from calls, pay-downs and maturities of held-to-maturity securities	58,245	51,439	46,322
Net change in interest-bearing time deposits in other banks	1,242	1,495	750
Net change in loans	(125,189)	(73,932)	(150,625)
Purchase of premises and equipment	(6,873)	(2,796)	(5,736)
Proceeds from sale of premises and equipment	9	209	15
Proceeds from sale of foreclosed assets	165
Net redemptions (purchases) of Federal Home Loan Bank and Federal Reserve Bank stock	(4,276)	(1,973)	(4,875)
Proceeds from sale of other real estate owned	5,461	3,017	2,266
Purchase of bank-owned life insurance	(15,000)	(14,500)
Net cash (used in) investing activities	(222,434)	(140,689)	(266,941)
Cash flows (to) from financing activities
Net increase (decrease) in deposits	123,224	39,082	147,952
Net change in federal funds purchased and retail repurchase agreements	8,177	(4,150)	(4,539)
Net borrowings (repayments) on Federal Home Loan Bank line of credit	79,996	114,149	128,895
Principal repayments on Federal Home Loan Bank term advances	(1,300)	(25,221)	(36,035)
Borrowings on bank stock loan	2,500	6,000	5,014
Principal repayments on bank stock loan	(1,000)	(33,218)	(1,554)
Proceeds from issuance of common stock, net		23,643	38,945
Proceeds from exercise of employee stock options	1,215	112
Issuance of employee stock loan			(1,215)
Principal payments on employee stock loan	121		973
Redemption of Series C preferred stock		(16,372)
Net change in contractual obligations	(537)	(589)	(53)
Dividends paid on preferred stock		(42)	(164)
Excess tax benefits as a result of the distribution of common stock in termination of the restricted stock unit plan recognized as an increase in additional paid-in capital			224
Excess tax benefits as a result of the exercise of employee stock options		13
Net cash provided by (used in) financing activities	212,396	103,407	278,443
Net change in cash and cash equivalents	17,100	(21,734)	25,122
Cash and cash equivalents, beginning of period	35,095	56,829	31,707
Ending cash and cash equivalents	52,195	35,095	56,829
Supplemental cash flow information:
Interest paid	15,041	8,943	6,670
Income taxes paid, net of refunds	6,438	3,212	2,938
Supplemental noncash disclosures:
Other real estate owned acquired in settlement of loans	4,562	3,006	3,164
Preferred stock dividends payable at period end			41
Prairie State Bancshares, Inc. [Member]
Cash flows (to) from investing activities
Net cash paid for acquisition	(6,744)
First Independence Corporation and Subsidiary [Member]
Cash flows (to) from investing activities
Net cash paid for acquisition			(9,046)
Supplemental noncash disclosures:
Total fair value of assets acquired, net of cash			129,341
Total fair value of liabilities acquired			$ 119,613
Eastman National Bancshares, Inc. [Member]
Cash flows (to) from investing activities
Net cash paid for acquisition	6,108
Supplemental noncash disclosures:
Total fair value of assets acquired, net of cash	267,039
Total fair value of liabilities acquired	234,337
Community First Bancshares, Inc. [Member]
Cash flows (to) from investing activities
Net cash paid for acquisition		(2,971)
Supplemental noncash disclosures:
Total fair value of assets acquired, net of cash		462,936
Total fair value of liabilities acquired		$ 419,641
Cache Holdings, Inc. [Member]
Cash flows (to) from investing activities
Net cash paid for acquisition	(2,857)
Supplemental noncash disclosures:
Total fair value of assets acquired, net of cash	333,140
Total fair value of liabilities acquired	291,056
Prairie State Bancshares, Inc. [Member]
Supplemental noncash disclosures:
Total fair value of assets acquired, net of cash	147,248
Total fair value of liabilities acquired	$ 125,591