FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) - USD ($)
$ in Thousands |
Sep. 30, 2016 |
Jun. 30, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Dec. 31, 2014 |
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
|
|
|
|
| Derivative Financial Instruments, Liabilities, Fair Value Disclosure |
$ 28,657
|
|
$ 14,179
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Investment securities held-to-maturity |
628,497
|
|
726,259
|
|
|
|
| Other investments |
51,170
|
|
53,725
|
|
|
|
| FDIC indemnification asset |
13,287
|
$ 14,504
|
17,630
|
$ 18,931
|
$ 20,338
|
$ 22,666
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
1,492,011
|
|
1,413,404
|
|
|
|
| Savings |
2,005,407
|
|
1,945,805
|
|
|
|
| Time |
1,346,736
|
|
1,406,124
|
|
|
|
| Carrying value |
|
|
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Cash and short-term investments |
134,747
|
|
148,575
|
|
|
|
| Investment securities held-to-maturity |
628,497
|
|
726,259
|
|
|
|
| Other investments |
51,170
|
|
53,725
|
|
|
|
| Loans held for sale |
17,414
|
|
20,957
|
|
|
|
| Loans and leases, net of ALLL |
5,731,893
|
|
5,335,362
|
|
|
|
| FDIC indemnification asset |
13,287
|
|
17,630
|
|
|
|
| Interest Receivable |
18,071
|
|
16,995
|
|
|
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
1,492,011
|
|
1,413,404
|
|
|
|
| Interest-bearing demand |
1,494,529
|
|
1,414,291
|
|
|
|
| Savings |
2,005,407
|
|
1,945,805
|
|
|
|
| Time |
1,346,736
|
|
1,406,124
|
|
|
|
| Total deposits |
6,338,683
|
|
6,179,624
|
|
|
|
| Short-term borrowings |
926,236
|
|
938,425
|
|
|
|
| Long-term debt |
119,549
|
|
119,540
|
|
|
|
| Interest Payable |
3,523
|
|
5,003
|
|
|
|
| Fair value |
|
|
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Cash and short-term investments |
134,747
|
|
148,575
|
|
|
|
| Investment securities held-to-maturity |
645,751
|
|
731,951
|
|
|
|
| Loans held for sale |
17,414
|
|
20,957
|
|
|
|
| Loans and leases, net of ALLL |
5,787,327
|
|
5,381,065
|
|
|
|
| FDIC indemnification asset |
7,455
|
|
9,756
|
|
|
|
| Interest Receivable |
18,071
|
|
16,995
|
|
|
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
1,492,011
|
|
1,413,404
|
|
|
|
| Interest-bearing demand |
1,494,529
|
|
1,414,291
|
|
|
|
| Savings |
2,005,407
|
|
1,945,805
|
|
|
|
| Time |
1,349,546
|
|
1,406,489
|
|
|
|
| Total deposits |
6,341,493
|
|
6,179,989
|
|
|
|
| Short-term borrowings |
926,236
|
|
938,425
|
|
|
|
| Long-term debt |
124,890
|
|
118,691
|
|
|
|
| Interest Payable |
3,523
|
|
5,003
|
|
|
|
| Fair Value, Inputs, Level 1 [Member] | Fair value |
|
|
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Cash and short-term investments |
134,747
|
|
148,575
|
|
|
|
| Investment securities held-to-maturity |
0
|
|
0
|
|
|
|
| Loans held for sale |
0
|
|
0
|
|
|
|
| Loans and leases, net of ALLL |
0
|
|
0
|
|
|
|
| FDIC indemnification asset |
0
|
|
0
|
|
|
|
| Interest Receivable |
0
|
|
0
|
|
|
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
0
|
|
0
|
|
|
|
| Interest-bearing demand |
0
|
|
0
|
|
|
|
| Savings |
0
|
|
0
|
|
|
|
| Time |
0
|
|
0
|
|
|
|
| Total deposits |
0
|
|
0
|
|
|
|
| Short-term borrowings |
926,236
|
|
938,425
|
|
|
|
| Long-term debt |
0
|
|
0
|
|
|
|
| Interest Payable |
640
|
|
113
|
|
|
|
| Fair Value, Inputs, Level 2 [Member] | Fair value |
|
|
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Cash and short-term investments |
0
|
|
0
|
|
|
|
| Investment securities held-to-maturity |
645,751
|
|
731,951
|
|
|
|
| Loans held for sale |
17,414
|
|
20,957
|
|
|
|
| Loans and leases, net of ALLL |
0
|
|
0
|
|
|
|
| FDIC indemnification asset |
0
|
|
0
|
|
|
|
| Interest Receivable |
5,423
|
|
5,791
|
|
|
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
1,492,011
|
|
1,413,404
|
|
|
|
| Interest-bearing demand |
1,494,529
|
|
1,414,291
|
|
|
|
| Savings |
2,005,407
|
|
1,945,805
|
|
|
|
| Time |
1,349,546
|
|
1,406,489
|
|
|
|
| Total deposits |
6,341,493
|
|
6,179,989
|
|
|
|
| Short-term borrowings |
0
|
|
0
|
|
|
|
| Long-term debt |
124,890
|
|
118,691
|
|
|
|
| Interest Payable |
2,883
|
|
4,890
|
|
|
|
| Fair Value, Inputs, Level 3 [Member] | Fair value |
|
|
|
|
|
|
| Financial assets |
|
|
|
|
|
|
| Cash and short-term investments |
0
|
|
0
|
|
|
|
| Investment securities held-to-maturity |
0
|
|
0
|
|
|
|
| Loans held for sale |
0
|
|
0
|
|
|
|
| Loans and leases, net of ALLL |
5,787,327
|
|
5,381,065
|
|
|
|
| FDIC indemnification asset |
7,455
|
|
9,756
|
|
|
|
| Interest Receivable |
12,648
|
|
11,204
|
|
|
|
| Deposits |
|
|
|
|
|
|
| Noninterest-bearing |
0
|
|
0
|
|
|
|
| Interest-bearing demand |
0
|
|
0
|
|
|
|
| Savings |
0
|
|
0
|
|
|
|
| Time |
0
|
|
0
|
|
|
|
| Total deposits |
0
|
|
0
|
|
|
|
| Short-term borrowings |
0
|
|
0
|
|
|
|
| Long-term debt |
0
|
|
0
|
|
|
|
| Interest Payable |
$ 0
|
|
$ 0
|
|
|
|