Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Assets [Abstract]
Interest bearing deposits - time		$ 593	$ 2,739
Equity securities at fair value		285	0
Trading securities		0	455
Securities available for sale		436,957	522,925
Federal Home Loan Bank and Federal Reserve Bank Stock		18,355	15,543
Liabilities [Abstract]
Other borrowings		79,688	54,600
Subordinated debentures		39,371	35,569
Reciprocal deposits included in deposits with no stated maturity		44,681	12,992
Reciprocal deposits included in deposits with stated maturity		47,954	37,987
Recorded Book Balance [Member]
Assets [Abstract]
Cash and due from banks		35,180	36,994
Interest bearing deposits		17,990	17,744
Interest bearing deposits - time		593	2,739
Equity securities at fair value		285
Trading securities			455
Securities available for sale		436,957	522,925
Federal Home Loan Bank and Federal Reserve Bank Stock		18,355	15,543
Net loans and loans held for sale		2,579,502	2,035,666
Accrued interest receivable		10,791	8,609
Derivative financial instruments		7,734	3,080
Liabilities [Abstract]
Deposits with no stated maturity	[1]	2,143,552	1,845,716
Deposits with stated maturity	[1]	655,091	554,818
Other borrowings		79,688	54,600
Subordinated debentures		39,371	35,569
Accrued interest payable		1,463	892
Derivative financial instruments		2,696	1,292
Fair Value [Member]
Assets [Abstract]
Cash and due from banks		35,180	36,994
Interest bearing deposits		17,990	17,744
Interest bearing deposits - time		593	2,740
Equity securities at fair value		285
Trading securities			455
Securities available for sale		436,957	522,925
Net loans and loans held for sale		2,533,221	1,962,937
Accrued interest receivable		10,791	8,609
Derivative financial instruments		7,734	3,080
Liabilities [Abstract]
Deposits with no stated maturity		2,143,552	1,845,716
Deposits with stated maturity		649,709	551,489
Other borrowings		79,275	54,918
Subordinated debentures		36,888	29,946
Accrued interest payable		1,463	892
Derivative financial instruments		2,696	1,292
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Cash and due from banks		35,180	36,994
Interest bearing deposits		17,990	17,744
Interest bearing deposits - time		0	0
Equity securities at fair value		285
Trading securities			455
Securities available for sale		0	898
Net loans and loans held for sale		0	0
Accrued interest receivable		1	1
Derivative financial instruments		0	0
Liabilities [Abstract]
Deposits with no stated maturity		2,143,552	1,845,716
Deposits with stated maturity		0	0
Other borrowings		0	0
Subordinated debentures		0	0
Accrued interest payable		110	48
Derivative financial instruments		0	0
Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Cash and due from banks		0	0
Interest bearing deposits		0	0
Interest bearing deposits - time		593	2,740
Equity securities at fair value		0
Trading securities			0
Securities available for sale		436,957	522,027
Net loans and loans held for sale		41,325	39,436
Accrued interest receivable		2,383	2,192
Derivative financial instruments		7,734	3,080
Liabilities [Abstract]
Deposits with no stated maturity		0	0
Deposits with stated maturity		649,709	551,489
Other borrowings		79,275	54,918
Subordinated debentures		36,888	29,946
Accrued interest payable		1,353	844
Derivative financial instruments		2,696	1,292
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Cash and due from banks		0	0
Interest bearing deposits		0	0
Interest bearing deposits - time		0	0
Equity securities at fair value		0
Trading securities			0
Securities available for sale		0	0
Net loans and loans held for sale		2,491,896	1,923,501
Accrued interest receivable		8,407	6,416
Derivative financial instruments		0	0
Liabilities [Abstract]
Deposits with no stated maturity		0	0
Deposits with stated maturity		0	0
Other borrowings		0	0
Subordinated debentures		0	0
Accrued interest payable		0	0
Derivative financial instruments		$ 0	$ 0

[1] Deposits with no stated maturity include reciprocal deposits with a recorded book balance of $44.681 million and $12.992 million at September 30, 2018 and December 31, 2017, respectively. Deposits with a stated maturity include reciprocal deposits with a recorded book balance of $47.954 million and $37.987 million September 30, 2018 and December 31, 2017, respectively.