SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Information about reportable segments
Net interest income	$ 209,413	$ 181,684	$ 165,500
Provision for loan losses	4,736	7,205	9,790
Noninterest income	89,222	88,792	83,535
Amortization of intangible assets	4,381	5,957	8,170
Goodwill Impairment	0	0	3,079
Other operating expenses	185,991	170,929	174,929
Income (Loss) before income taxes	103,527	86,385	53,067
Assets	6,488,275	5,444,506	5,402,813
Goodwill	345,050	297,692	297,692
Banking [Member]
Information about reportable segments
Net interest income	209,302	181,582	165,429
Provision for loan losses	4,736	7,205	9,790
Noninterest income	46,921	49,342	47,133
Amortization of intangible assets	3,393	5,081	7,176
Goodwill Impairment	0		0
Other operating expenses	152,468	140,267	143,760
Income (Loss) before income taxes	95,626	78,371	51,836
Assets	6,461,694	5,420,990	5,378,916
Goodwill	334,554	287,412	287,412
Other [Member]
Information about reportable segments
Net interest income	111	102	71
Provision for loan losses	0	0	0
Noninterest income	44,142	41,066	37,708
Amortization of intangible assets	988	876	994
Goodwill Impairment	0		3,079
Other operating expenses	35,364	32,278	32,475
Income (Loss) before income taxes	7,901	8,014	1,231
Assets	38,557	33,129	35,201
Goodwill	10,496	10,280	10,280
Elimination [Member]
Information about reportable segments
Net interest income	0	0	0
Provision for loan losses	0	0	0
Noninterest income	(1,841)	(1,616)	(1,306)
Amortization of intangible assets	0	0	0
Goodwill Impairment	0		0
Other operating expenses	(1,841)	(1,616)	(1,306)
Income (Loss) before income taxes	0	0	0
Assets	(11,976)	(9,613)	(11,304)
Goodwill	$ 0	$ 0	$ 0