STOCKHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Total capital to risk-weighted assets
Actual, Amount	$ 456,314	$ 347,187
Tier 1 capital to risk-weighted assets
Actual, Amount	387,548	314,320
Reconciliation of total stockholders' equity to the bank's regulatory capital
Total stockholders' equity per consolidated financial statements	667,265	551,808	387,323	384,067
Adjustments for Bank Tier 1 Capital:
Holding company equity adjustment	(5,172)	(34,117)
Net unrealized gain on available for sale securities	(6,712)	(3,960)
Net unrealized loss on cash flow hedges	9,263	7,549
Disallowed goodwill and other intangible assets	(248,586)	(198,715)
Disallowed deferred taxes	(28,510)	(8,245)
Total Bank Tier 1 Capital	387,548	314,320
Adjustments for total capital:
Qualifying subordinated debt	35,000
Includible allowances for loan losses	33,299	32,519
Net unrealized loss (gain) on available for sale securities includible in Tier 2 capital	(467)	(348)
Total Bank capital per regulatory reporting	456,314	347,187
Bank
Total capital to risk-weighted assets
Actual, Amount	456,314	347,187
Actual, Ratio (as a percent)	11.79%	11.29%
Minimum Capital Requirement, Amount	309,684	246,014
Minimum Capital Requirement, Ratio (as a percent)	8.00%	8.00%
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Amount	387,105	307,517
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent)	10.00%	10.00%
Tier 1 capital to risk-weighted assets
Actual, Amount	387,548	314,320
Actual, Ratio (as a percent)	10.01%	10.22%
Minimum Capital Requirement, Amount	154,842	123,022
Minimum Capital Requirement, Ratio (as a percent)	4.00%	4.00%
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Amount	232,263	184,532
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent)	6.00%	6.00%
Tier 1 capital to average assets
Actual, Amount	387,548	314,320
Actual, Ratio (as a percent)	7.46%	8.41%
Minimum Capital Requirement, Amount	207,874	149,498
Minimum Capital Requirement, Ratio (as a percent)	4.00%	4.00%
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Amount	259,842	186,873
Minimum to be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent)	5.00%	5.00%
Adjustments for Bank Tier 1 Capital:
Total Bank Tier 1 Capital	387,548	314,320
Adjustments for total capital:
Total Bank capital per regulatory reporting	$ 456,314	$ 347,187