Loans and Allowance for Loan Losses - Credit Quality Indicators by Portfolio Class (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	$ 3,337,262	$ 3,078,076
Purchased credit impaired loans	78,313	88,835
Total loans	3,415,575	3,166,911
Pass
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	3,183,477	2,940,174
Total loans	3,183,477	2,940,174
Watch
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	122,964	114,401
Purchased credit impaired loans	50,667	56,848
Total loans	173,631	171,249
Substandard
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	30,821	23,501
Purchased credit impaired loans	27,646	31,987
Total loans	58,467	55,488
Commercial and Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	811,288	712,931
Purchased credit impaired loans	1,766	2,144
Total loans	813,054	715,075
Commercial and Industrial | Pass
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	746,253	657,595
Commercial and Industrial | Watch
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	59,476	50,946
Purchased credit impaired loans	1,187	1,499
Commercial and Industrial | Substandard
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	5,559	4,390
Purchased credit impaired loans	579	645
Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	515,410	440,598
Purchased credit impaired loans	7,061	7,728
Total loans	522,471	448,326
Construction | Pass
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	499,370	431,242
Construction | Watch
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	14,278	7,388
Purchased credit impaired loans	3,332	3,324
Construction | Substandard
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	1,762	1,968
Purchased credit impaired loans	3,729	4,404
Residential Real Estate | 1-to-4 Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	507,146	457,491
Purchased credit impaired loans	21,012	23,498
Total loans	528,158	480,989
Residential Real Estate | Residential Line of Credit
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	208,668	194,986
Total loans	208,668	194,986
Residential Real Estate | Multi-Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	57,328	62,354
Purchased credit impaired loans	16	20
Total loans	57,344	62,374
Residential Real Estate | Pass | 1-to-4 Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	490,856	440,202
Residential Real Estate | Pass | Residential Line of Credit
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	205,614	192,427
Residential Real Estate | Pass | Multi-Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	56,245	61,234
Residential Real Estate | Watch | 1-to-4 Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	8,625	9,522
Purchased credit impaired loans	16,721	20,284
Residential Real Estate | Watch | Residential Line of Credit
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	1,632	1,184
Residential Real Estate | Watch | Multi-Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	133	142
Residential Real Estate | Substandard | 1-to-4 Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	7,665	7,767
Purchased credit impaired loans	4,291	3,214
Residential Real Estate | Substandard | Residential Line of Credit
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	1,422	1,375
Residential Real Estate | Substandard | Multi-Family Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	950	978
Purchased credit impaired loans	16	20
Commercial Real Estate | Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	462,547	483,910
Purchased credit impaired loans	8,325	11,962
Total loans	470,872	495,872
Commercial Real Estate | Non-Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	582,580	533,424
Purchased credit impaired loans	18,049	18,164
Total loans	600,629	551,588
Commercial Real Estate | Pass | Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	434,025	451,140
Commercial Real Estate | Pass | Non-Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	565,195	517,253
Commercial Real Estate | Watch | Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	20,435	28,308
Purchased credit impaired loans	4,488	4,631
Commercial Real Estate | Watch | Non-Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	16,096	14,199
Purchased credit impaired loans	7,465	7,359
Commercial Real Estate | Substandard | Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	8,087	4,462
Purchased credit impaired loans	3,837	7,331
Commercial Real Estate | Substandard | Non-Owner Occupied
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	1,289	1,972
Purchased credit impaired loans	10,584	10,805
Consumer and Other
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	192,295	192,382
Purchased credit impaired loans	22,084	25,319
Total loans	214,379	217,701
Consumer and Other | Pass
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	185,919	189,081
Consumer and Other | Watch
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	2,289	2,712
Purchased credit impaired loans	17,474	19,751
Consumer and Other | Substandard
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, excluding purchased credit impaired loans	4,087	589
Purchased credit impaired loans	$ 4,610	$ 5,568