PREMISES AND EQUIPMENT (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Premises and equipment disclosures
Premises and equipment, gross	$ 171,720,000	$ 178,588,000
Accumulated depreciation and amortization	(64,203,000)	(59,662,000)
Premises and equipment, net	107,517,000	118,926,000
Depreciation expense	13,200,000	12,100,000	13,800,000
Land
Premises and equipment disclosures
Premises and equipment, gross	15,545,000	15,545,000
Office buildings
Premises and equipment disclosures
Premises and equipment, gross	82,418,000	92,041,000
Leasehold improvements
Premises and equipment disclosures
Premises and equipment, gross	29,635,000	25,084,000
Furniture and Fixtures
Premises and equipment disclosures
Premises and equipment, gross	$ 44,122,000	$ 45,918,000
Estimated useful life	7 years
Office Equipment
Premises and equipment disclosures
Estimated useful life	5 years
Building and Building Improvements
Premises and equipment disclosures
Estimated useful life	25 years