SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Results of Operations [Abstract]
Net interest revenue	$ 104,741	$ 109,912	$ 210,351	$ 219,349
Provision for credit losses	6,000	32,240	16,000	85,719
Net interest revenue after provision for credit losses	98,741	77,672	194,351	133,630
Noninterest revenue	66,468	75,144	138,828	143,455
Noninterest expense	136,506	137,069	272,186	267,079
Income before income taxes	28,703	15,747	60,993	10,006
Income tax expense (benefit)	8,079	2,921	17,503	(2,326)
Net income	20,624	12,826	43,490	12,332
Selected Financial Information [Abstract]
Total assets at end of period	13,147,818	13,367,050	13,147,818	13,367,050	12,995,851	[1]
Depreciation and amortization	7,453	8,148	15,045	16,476
Community Banking [Member]
Results of Operations [Abstract]
Net interest revenue	106,649	102,880	214,301	205,543
Provision for credit losses	4,288	32,534	14,516	85,775
Net interest revenue after provision for credit losses	102,361	70,346	199,785	119,768
Noninterest revenue	29,745	40,913	60,930	68,905
Noninterest expense	84,057	91,936	183,116	174,654
Income before income taxes	48,049	19,323	77,599	14,019
Income tax expense (benefit)	15,721	4,063	25,033	1,962
Net income	32,328	15,260	52,566	12,057
Selected Financial Information [Abstract]
Total assets at end of period	10,606,406	10,483,137	10,606,406	10,483,137
Depreciation and amortization	5,911	6,107	11,933	12,381
Insurance Agencies [Member]
Results of Operations [Abstract]
Net interest revenue	76	84	149	179
Provision for credit losses	0	0	0	0
Net interest revenue after provision for credit losses	76	84	149	179
Noninterest revenue	22,905	22,890	46,055	45,427
Noninterest expense	19,463	19,011	38,161	37,063
Income before income taxes	3,518	3,963	8,043	8,543
Income tax expense (benefit)	1,404	1,576	3,223	3,401
Net income	2,114	2,387	4,820	5,142
Selected Financial Information [Abstract]
Total assets at end of period	179,106	171,122	179,106	171,122
Depreciation and amortization	842	972	1,716	1,946
General Corporate and Other [Member]
Results of Operations [Abstract]
Net interest revenue	(1,984)	6,948	(4,099)	13,627
Provision for credit losses	1,712	(294)	1,484	(56)
Net interest revenue after provision for credit losses	(3,696)	7,242	(5,583)	13,683
Noninterest revenue	13,818	11,341	31,843	29,123
Noninterest expense	32,986	26,122	50,909	55,362
Income before income taxes	(22,864)	(7,539)	(24,649)	(12,556)
Income tax expense (benefit)	(9,046)	(2,718)	(10,753)	(7,689)
Net income	(13,818)	(4,821)	(13,896)	(4,867)
Selected Financial Information [Abstract]
Total assets at end of period	2,362,306	2,712,791	2,362,306	2,712,791
Depreciation and amortization	$ 700	$ 1,069	$ 1,396	$ 2,149

[1] Derived from audited financial statements.