Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans by Segment (Detail) - USD ($) $ in Thousands |
Mar. 31, 2018 |
Dec. 31, 2017 |
Mar. 31, 2017 |
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
$ 5,381,305
|
$ 5,407,376
|
$ 4,907,961
|
Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
1,131,594
|
|
1,148,460
|
Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
246,961
|
|
240,122
|
Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
1,434,623
|
|
1,217,398
|
Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
2,027,072
|
|
1,761,101
|
Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total |
541,055
|
|
$ 540,880
|
Acquired Loans [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
2,529
|
2,570
|
|
Financing Receivable, Recorded Investment, Current |
381,661
|
397,445
|
|
Total |
384,190
|
400,015
|
|
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
448
|
449
|
|
Financing Receivable, Recorded Investment, Current |
37,954
|
40,193
|
|
Total |
38,402
|
40,642
|
|
Acquired Loans [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
0
|
0
|
|
Financing Receivable, Recorded Investment, Current |
1,120
|
5,963
|
|
Total |
1,120
|
5,963
|
|
Acquired Loans [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
968
|
945
|
|
Financing Receivable, Recorded Investment, Current |
212,666
|
219,306
|
|
Total |
213,634
|
220,251
|
|
Acquired Loans [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
1,000
|
1,077
|
|
Financing Receivable, Recorded Investment, Current |
124,463
|
125,834
|
|
Total |
125,463
|
126,911
|
|
Acquired Loans [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
113
|
99
|
|
Financing Receivable, Recorded Investment, Current |
5,458
|
6,149
|
|
Total |
5,571
|
6,248
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
196
|
190
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
11
|
6
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
119
|
148
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
66
|
36
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
121
|
36
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
7
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
110
|
9
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
11
|
20
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
66
|
109
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
26
|
0
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
21
|
83
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
19
|
26
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
2,146
|
2,235
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
411
|
436
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
718
|
705
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
1,000
|
1,077
|
|
Acquired Loans [Member] | Non Accrual Loans [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
17
|
17
|
|
Originated Loans [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
48,690
|
41,362
|
|
Financing Receivable, Recorded Investment, Current |
4,948,425
|
4,965,999
|
|
Total |
4,997,115
|
5,007,361
|
|
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
26,652
|
19,220
|
|
Financing Receivable, Recorded Investment, Current |
1,066,540
|
1,103,521
|
|
Total |
1,093,192
|
1,122,741
|
|
Originated Loans [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
0
|
199
|
|
Financing Receivable, Recorded Investment, Current |
245,841
|
242,706
|
|
Total |
245,841
|
242,905
|
|
Originated Loans [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
10,681
|
12,944
|
|
Financing Receivable, Recorded Investment, Current |
1,210,308
|
1,193,175
|
|
Total |
1,220,989
|
1,206,119
|
|
Originated Loans [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
8,513
|
5,472
|
|
Financing Receivable, Recorded Investment, Current |
1,893,096
|
1,886,713
|
|
Total |
1,901,609
|
1,892,185
|
|
Originated Loans [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Financing Receivable Recorded Investment Equal To Or Greater Than Thirty Days Past Due |
2,844
|
3,527
|
|
Financing Receivable, Recorded Investment, Current |
532,640
|
539,884
|
|
Total |
535,484
|
543,411
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
8,132
|
9,292
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
2,163
|
378
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
199
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
2,849
|
4,618
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
1,751
|
2,198
|
|
Originated Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
1,369
|
1,899
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
2,265
|
1,883
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
23
|
61
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
996
|
1,025
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
783
|
28
|
|
Originated Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
463
|
769
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
1,889
|
1,745
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
168
|
40
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
649
|
1,076
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
304
|
6
|
|
Originated Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
768
|
623
|
|
Originated Loans [Member] | Non Accrual Loans [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
36,404
|
28,442
|
|
Originated Loans [Member] | Non Accrual Loans [Member] | Commercial, financial, agricultural and other [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
24,298
|
18,741
|
|
Originated Loans [Member] | Non Accrual Loans [Member] | Real estate construction [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
0
|
0
|
|
Originated Loans [Member] | Non Accrual Loans [Member] | Residential real estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
6,187
|
6,225
|
|
Originated Loans [Member] | Non Accrual Loans [Member] | Commercial Real Estate [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
5,675
|
3,240
|
|
Originated Loans [Member] | Non Accrual Loans [Member] | Loans to individuals [Member] |
|
|
|
Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
|
Total past due and nonaccrual |
$ 244
|
$ 236
|
|