SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Results of Operations [Abstract]
Net interest revenue	$ 98,213	$ 104,741	$ 196,291	$ 210,351
Provision for credit losses	3,000	6,000	7,000	16,000	28,000
Net interest revenue, after provision for credit losses	95,213	98,741	189,291	194,351
Noninterest revenue	76,109	66,468	147,427	138,828
Noninterest expense	142,251	136,506	277,622	272,186
Income (loss) before income taxes	29,071	28,703	59,096	60,993
Income tax expense (benefit)	8,316	8,079	17,536	17,503
Net income (loss)	20,755	20,624	41,560	43,490
Selected Financial Information [Abstract]
Total assets at end of period	13,217,705	13,147,818	13,217,705	13,147,818	13,397,198	[1]
Depreciation and amortization	7,327	7,453	14,781	15,044
Community Banking [Member]
Results of Operations [Abstract]
Net interest revenue	92,725	98,408	184,969	197,739
Provision for credit losses	2,139	4,288	6,240	14,516
Net interest revenue, after provision for credit losses	90,586	94,120	178,729	183,223
Noninterest revenue	26,720	27,546	53,227	56,710
Noninterest expense	76,557	81,863	167,762	178,564
Income (loss) before income taxes	40,749	39,803	64,194	61,369
Income tax expense (benefit)	13,447	12,666	21,197	18,909
Net income (loss)	27,302	27,137	42,997	42,460
Selected Financial Information [Abstract]
Total assets at end of period	9,928,278	9,986,180	9,928,278	9,986,180
Depreciation and amortization	5,726	5,892	11,516	11,862
Insurance Agencies [Member]
Results of Operations [Abstract]
Net interest revenue	40	76	90	149
Net interest revenue, after provision for credit losses	40	76	90	149
Noninterest revenue	25,793	22,905	52,323	46,055
Noninterest expense	21,991	19,463	43,398	38,161
Income (loss) before income taxes	3,842	3,518	9,015	8,043
Income tax expense (benefit)	1,542	1,404	3,619	3,223
Net income (loss)	2,300	2,114	5,396	4,820
Selected Financial Information [Abstract]
Total assets at end of period	194,050	179,106	194,050	179,106
Depreciation and amortization	884	842	1,778	1,716
General Corporate And Other [Member]
Results of Operations [Abstract]
Net interest revenue	5,448	6,257	11,232	12,463
Provision for credit losses	861	1,712	760	1,484
Net interest revenue, after provision for credit losses	4,587	4,545	10,472	10,979
Noninterest revenue	23,596	16,017	41,877	36,063
Noninterest expense	43,703	35,180	66,462	55,461
Income (loss) before income taxes	(15,520)	(14,618)	(14,113)	(8,419)
Income tax expense (benefit)	(6,673)	(5,991)	(7,280)	(4,629)
Net income (loss)	(8,847)	(8,627)	(6,833)	(3,790)
Selected Financial Information [Abstract]
Total assets at end of period	3,095,377	2,982,532	3,095,377	2,982,532
Depreciation and amortization	$ 717	$ 719	$ 1,487	$ 1,466

[1] Derived from audited financial statements.See accompanying notes to consolidated financial statements.