Loans and Allowance for Credit Losses - Credit Risk Profile by Creditworthiness (Detail) - USD ($) $ in Thousands |
Dec. 31, 2018 |
Dec. 31, 2017 |
Originated Loans [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
$ 5,275,296
|
$ 5,007,361
|
Originated Loans [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,160,953
|
4,896,832
|
Originated Loans [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
79,294
|
41,518
|
Originated Loans [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
35,049
|
64,605
|
Originated Loans [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
4,406
|
Originated Loans [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
114,343
|
110,529
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,100,947
|
1,122,741
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,055,394
|
1,061,147
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
33,723
|
26,757
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
11,830
|
30,431
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
4,406
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
45,553
|
61,594
|
Originated Loans [Member] | Real Estate Construction [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
353,008
|
242,905
|
Originated Loans [Member] | Real Estate Construction [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
337,367
|
242,905
|
Originated Loans [Member] | Real Estate Construction [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
15,641
|
0
|
Originated Loans [Member] | Real Estate Construction [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Real Estate Construction [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Real Estate Construction [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
15,641
|
0
|
Originated Loans [Member] | Residential real estate [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,313,645
|
1,206,119
|
Originated Loans [Member] | Residential real estate [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,302,912
|
1,194,352
|
Originated Loans [Member] | Residential real estate [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,026
|
1,435
|
Originated Loans [Member] | Residential real estate [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
9,707
|
10,332
|
Originated Loans [Member] | Residential real estate [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Residential real estate [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
10,733
|
11,767
|
Originated Loans [Member] | Commercial real estate [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,922,349
|
1,892,185
|
Originated Loans [Member] | Commercial real estate [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
1,880,139
|
1,855,253
|
Originated Loans [Member] | Commercial real estate [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
28,904
|
13,326
|
Originated Loans [Member] | Commercial real estate [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
13,306
|
23,606
|
Originated Loans [Member] | Commercial real estate [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Commercial real estate [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
42,210
|
36,932
|
Originated Loans [Member] | Loans To Individuals [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
585,347
|
543,411
|
Originated Loans [Member] | Loans To Individuals [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
585,141
|
543,175
|
Originated Loans [Member] | Loans To Individuals [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Loans To Individuals [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
206
|
236
|
Originated Loans [Member] | Loans To Individuals [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Originated Loans [Member] | Loans To Individuals [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
206
|
236
|
Acquired Loans [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
498,843
|
400,015
|
Acquired Loans [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
485,951
|
386,127
|
Acquired Loans [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
7,700
|
9,882
|
Acquired Loans [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,192
|
4,006
|
Acquired Loans [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
12,892
|
13,888
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
37,526
|
40,642
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
31,399
|
34,573
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,890
|
5,567
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
237
|
502
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
6,127
|
6,069
|
Acquired Loans [Member] | Real Estate Construction [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,970
|
5,963
|
Acquired Loans [Member] | Real Estate Construction [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,337
|
5,963
|
Acquired Loans [Member] | Real Estate Construction [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
633
|
0
|
Acquired Loans [Member] | Real Estate Construction [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Real Estate Construction [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Real Estate Construction [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
633
|
0
|
Acquired Loans [Member] | Residential real estate [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
248,760
|
220,251
|
Acquired Loans [Member] | Residential real estate [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
245,637
|
217,824
|
Acquired Loans [Member] | Residential real estate [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
736
|
798
|
Acquired Loans [Member] | Residential real estate [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
2,387
|
1,629
|
Acquired Loans [Member] | Residential real estate [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Residential real estate [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
3,123
|
2,427
|
Acquired Loans [Member] | Commercial real estate [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
201,195
|
126,911
|
Acquired Loans [Member] | Commercial real estate [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
198,201
|
121,536
|
Acquired Loans [Member] | Commercial real estate [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
441
|
3,517
|
Acquired Loans [Member] | Commercial real estate [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
2,553
|
1,858
|
Acquired Loans [Member] | Commercial real estate [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Commercial real estate [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
2,994
|
5,375
|
Acquired Loans [Member] | Loans To Individuals [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,392
|
6,248
|
Acquired Loans [Member] | Loans To Individuals [Member] | Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
5,377
|
6,231
|
Acquired Loans [Member] | Loans To Individuals [Member] | Special Mention [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Loans To Individuals [Member] | Substandard [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
15
|
17
|
Acquired Loans [Member] | Loans To Individuals [Member] | Doubtful [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
0
|
0
|
Acquired Loans [Member] | Loans To Individuals [Member] | Total Non-Pass [Member] |
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
Loans and Leases Receivable, Gross |
$ 15
|
$ 17
|