Loans and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	$ 3,538,531	$ 3,166,911
Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	73,651	88,835
Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	8,355	8,101
30-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	12,311	15,063
90 Days or More and Accruing Interest
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	2,364	1,996
Financing Receivables Current
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	3,441,850	3,052,916
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	840,439	715,075
Commercial and Industrial | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	1,603	2,144
Commercial and Industrial | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	2,158	533
Commercial and Industrial | 30-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	2,491	5,859
Commercial and Industrial | 90 Days or More and Accruing Interest
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	120	90
Commercial and Industrial | Financing Receivables Current
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	834,067	706,449
Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	491,171	448,326
Construction | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	6,823	7,728
Construction | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	270	300
Construction | 30-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	337	1,412
Construction | 90 Days or More and Accruing Interest
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	17	241
Construction | Financing Receivables Current
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	483,724	438,645
Residential Real Estate | 1-to-4 Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	553,720	480,989
Residential Real Estate | 1-to-4 Family Mortgage | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	20,089	23,498
Residential Real Estate | 1-to-4 Family Mortgage | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	1,633	2,548
Residential Real Estate | Residential Line of Credit
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	214,741	194,986
Residential Real Estate | Residential Line of Credit | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	831	699
Residential Real Estate | Multi-Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	86,264	62,374
Residential Real Estate | Multi-Family Mortgage | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans		20
Residential Real Estate | 30-89 Days Past Due | 1-to-4 Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	4,170	4,678
Residential Real Estate | 30-89 Days Past Due | Residential Line of Credit
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	635	527
Residential Real Estate | 90 Days or More and Accruing Interest | 1-to-4 Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	875	956
Residential Real Estate | 90 Days or More and Accruing Interest | Residential Line of Credit
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	492	134
Residential Real Estate | Financing Receivables Current | 1-to-4 Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	526,953	449,309
Residential Real Estate | Financing Receivables Current | Residential Line of Credit
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	212,783	193,626
Residential Real Estate | Financing Receivables Current | Multi-Family Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	86,264	62,354
Commercial Real Estate | Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	504,149	495,872
Commercial Real Estate | Owner Occupied | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	7,483	11,962
Commercial Real Estate | Owner Occupied | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	2,203	2,582
Commercial Real Estate | Non-Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	628,336	551,588
Commercial Real Estate | Non-Owner Occupied | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	16,563	18,164
Commercial Real Estate | Non-Owner Occupied | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	1,206	1,371
Commercial Real Estate | 30-89 Days Past Due | Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	1,943	521
Commercial Real Estate | 30-89 Days Past Due | Non-Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	636	121
Commercial Real Estate | 90 Days or More and Accruing Interest | Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	111	358
Commercial Real Estate | Financing Receivables Current | Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	492,409	480,449
Commercial Real Estate | Financing Receivables Current | Non-Owner Occupied
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	609,931	531,932
Consumer and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	219,711	217,701
Consumer and Other | Purchased Credit Impaired
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	21,090	25,319
Consumer and Other | Non Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	54	68
Consumer and Other | 30-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	2,099	1,945
Consumer and Other | 90 Days or More and Accruing Interest
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	749	217
Consumer and Other | Financing Receivables Current
Financing Receivable Recorded Investment Past Due [Line Items]
Loans	$ 195,719	$ 190,152