FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 16,044	$ 26,423
Financial assets
Investment securities held-to-maturity	669,093	770,755
Other investments	75,945	71,492
Covered loans	495,265	702,926
FDIC indemnification asset	78,132	119,607
Deposits
Noninterest-bearing	1,141,016	1,102,774
Savings	1,593,895	1,623,614
Time	926,029	1,068,637
Carrying value
Financial assets
Cash and short-term investments	188,112	158,843
Investment securities held-to-maturity	669,093	770,755
Other investments	75,945	71,492
Loans held for sale	10,704	16,256
Loans - excluding covered loans	3,385,402	3,131,287
Covered loans	495,265	702,926
FDIC indemnification asset	78,132	119,607
Deposits
Noninterest-bearing	1,141,016	1,102,774
Interest-bearing demand	1,068,067	1,160,815
Savings	1,593,895	1,623,614
Time	926,029	1,068,637
Total deposits	4,729,007	4,955,840
Short-term borrowings	623,672	624,570
Long-term debt	61,088	75,202
Fair value
Financial assets
Cash and short-term investments	188,112	158,843
Investment securities held-to-maturity	661,685	778,474
Other investments	75,945	71,492
Loans held for sale	10,704	16,256
Loans - excluding covered loans	3,379,595	3,145,120
Covered loans	504,781	713,797
FDIC indemnification asset	57,978	106,380
Deposits
Noninterest-bearing	1,141,016	1,102,774
Interest-bearing demand	1,068,067	1,160,815
Savings	1,593,895	1,623,614
Time	921,933	1,072,201
Total deposits	4,724,911	4,959,404
Short-term borrowings	623,672	624,570
Long-term debt	63,338	78,941
Fair Value, Inputs, Level 1 [Member] | Fair value
Financial assets
Cash and short-term investments	188,112	158,843
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	623,672	624,570
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	661,685	778,474
Other investments	75,945	71,492
Loans held for sale	10,704	16,256
Loans - excluding covered loans	0	0
Covered loans	0	0
FDIC indemnification asset	0	0
Deposits
Noninterest-bearing	1,141,016	1,102,774
Interest-bearing demand	1,068,067	1,160,815
Savings	1,593,895	1,623,614
Time	921,933	1,072,201
Total deposits	4,724,911	4,959,404
Short-term borrowings	0	0
Long-term debt	63,338	78,941
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	3,379,595	3,145,120
Covered loans	504,781	713,797
FDIC indemnification asset	57,978	106,380
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