FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 13,427	$ 14,431
Financial assets
Investment securities held-to-maturity	890,806	837,272
Other investments	47,659	47,427
Covered loans	398,832	438,972
FDIC indemnification asset	39,003	45,091
Deposits
Noninterest-bearing	1,122,816	1,147,452
Savings	1,639,495	1,612,005
Time	956,049	952,327
Carrying value
Financial assets
Cash and short-term investments	171,196	143,450
Investment securities held-to-maturity	890,806	837,272
Other investments	47,659	47,427
Loans held for sale	6,171	8,114
Loans - excluding covered loans	3,571,180	3,461,812
Covered loans	398,832	438,972
FDIC indemnification asset	39,003	45,091
Deposits
Noninterest-bearing	1,122,816	1,147,452
Interest-bearing demand	1,102,029	1,125,723
Savings	1,639,495	1,612,005
Time	956,049	952,327
Total deposits	4,820,389	4,837,507
Short-term borrowings	835,093	748,749
Long-term debt	60,163	60,780
Fair value
Financial assets
Cash and short-term investments	171,196	143,450
Investment securities held-to-maturity	885,327	824,985
Other investments	47,659	47,427
Loans held for sale	6,171	8,114
Loans - excluding covered loans	3,564,373	3,455,776
Covered loans	404,861	451,545
FDIC indemnification asset	30,387	34,820
Deposits
Noninterest-bearing	1,122,816	1,147,452
Interest-bearing demand	1,102,029	1,125,723
Savings	1,639,495	1,612,005
Time	957,047	951,220
Total deposits	4,821,387	4,836,400
Short-term borrowings	835,093	748,749
Long-term debt	61,787	62,706
Fair Value, Inputs, Level 1 [Member] | Fair value
Financial assets
Cash and short-term investments	171,196	143,450
Investment securities held-to-maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans - excluding covered loans	0	0
Covered loans	0	0
FDIC indemnification asset	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	835,093	748,749
Long-term debt	0	0
Fair Value, Inputs, Level 2 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	885,327	824,985
Other investments	47,659	47,427
Loans held for sale	6,171	8,114
Loans - excluding covered loans	0	0
Covered loans	0	0
FDIC indemnification asset	0	0
Deposits
Noninterest-bearing	1,122,816	1,147,452
Interest-bearing demand	1,102,029	1,125,723
Savings	1,639,495	1,612,005
Time	957,047	951,220
Total deposits	4,821,387	4,836,400
Short-term borrowings	0	0
Long-term debt	61,787	62,706
Fair Value, Inputs, Level 3 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans - excluding covered loans	3,564,373	3,455,776
Covered loans	404,861	451,545
FDIC indemnification asset	30,387	34,820
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