Allowance for Loan Losses - Summary of Changes in Loan Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	$ 31,594	$ 29,667	$ 31,083	$ 29,746
Charge-offs	(539)	(2,608)	(1,384)	(4,322)
Recoveries	565	247	1,054	743
Provision for Loan Losses	1,131	1,120	1,998	2,259
Balance at End of Period	32,751	28,426	32,751	28,426
Commercial Business
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	21,908	21,479	22,382	22,064
Charge-offs	(141)	(2,140)	(443)	(3,370)
Recoveries	454	85	826	359
Provision for Loan Losses	293	1,048	(251)	1,419
Balance at End of Period	22,514	20,472	22,514	20,472
Commercial Business | Commercial and Industrial
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	10,091	9,830	10,968	9,972
Charge-offs	(63)	(1,392)	(358)	(2,570)
Recoveries	452	85	675	359
Provision for Loan Losses	171	1,447	(634)	2,209
Balance at End of Period	10,651	9,970	10,651	9,970
Commercial Business | Owner-occupied Commercial Real Estate
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	4,216	4,092	3,661	4,370
Charge-offs	(78)	(398)	(85)	(450)
Recoveries	2	0	151	0
Provision for Loan Losses	14	(116)	427	(342)
Balance at End of Period	4,154	3,578	4,154	3,578
Commercial Business | Non-owner Occupied Commercial Real Estate
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	7,601	7,557	7,753	7,722
Charge-offs	0	(350)	0	(350)
Recoveries	0	0	0	0
Provision for Loan Losses	108	(283)	(44)	(448)
Balance at End of Period	7,709	6,924	7,709	6,924
One-to-four Family Residential
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	1,052	1,087	1,015	1,157
Charge-offs	0	0	0	0
Recoveries	1	1	1	2
Provision for Loan Losses	20	(138)	57	(209)
Balance at End of Period	1,073	950	1,073	950
Real Estate Construction and Land Development
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	2,337	1,871	2,156	1,871
Charge-offs	0	(1)	0	(154)
Recoveries	0	0	10	83
Provision for Loan Losses	150	161	321	231
Balance at End of Period	2,487	2,031	2,487	2,031
Real Estate Construction and Land Development | One-to-four Family Real Estate Construction
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	791	804	797	1,058
Charge-offs	0	0	0	(100)
Recoveries	0	0	10	83
Provision for Loan Losses	30	(50)	14	(287)
Balance at End of Period	821	754	821	754
Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	1,546	1,067	1,359	813
Charge-offs	0	(1)	0	(54)
Recoveries	0	0	0	0
Provision for Loan Losses	120	211	307	518
Balance at End of Period	1,666	1,277	1,666	1,277
Consumer
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	5,195	4,756	5,024	4,309
Charge-offs	(398)	(467)	(941)	(798)
Recoveries	110	161	217	299
Provision for Loan Losses	803	366	1,410	1,006
Balance at End of Period	5,710	4,816	5,710	4,816
Unallocated
Schedule of changes in allowance for loan losses
Balance at Beginning of Period	1,102	474	506	345
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for Loan Losses	(135)	(317)	461	(188)
Balance at End of Period	$ 967	$ 157	$ 967	$ 157