SECURITIES - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Investments [Line Items]
Federal Home Loan Bank stock, at cost	$ 490,228,000	$ 446,014,000
Commitments to purchase securities	45,500,000
Investment securities designated as having a continuous loss position for twelve months or more, unrealized losses	28,300,000	46,500,000
Investment securities designated as having a continuous loss position for twelve months or more, percentage below collective amortized cost	21.20%	24.00%
Investment securities designated as having a continuous loss position for twelve months or more, amortized cost	133,400,000	193,500,000
Proceeds from sales of held to maturity securities	284,406,000
Gain from sales of held to maturity securities	8,500,000
Total loss on OTTI of securities	18,124,000	26,456,000	106,248,000
Net loss on OTTI recognized in earnings	18,124,000	1,971,000	96,533,000
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	8,506,000	23,767,000
Common stock
Schedule of Investments [Line Items]
Amortized cost of marketable equity securities	40,300,000
Perpetual Preferred Stock
Schedule of Investments [Line Items]
Amortized cost of marketable equity securities	195,000
Capital trust notes
Schedule of Investments [Line Items]
Fair value	156,300,000
Number of pooled trust preferred securities	3
Pooled trust preferred securities with no excess subordination	2
Pooled trust preferred securities with excess subordination	1
Pooled trust preferred securities, excess subordination percentage	11.00%
Number of investment securities designated as having a continuous loss position for twelve months or more	11	11
Preferred stock
Schedule of Investments [Line Items]
Total loss on OTTI of securities	18,100,000	12,800,000
Trust Preferred Securities
Schedule of Investments [Line Items]
Total loss on OTTI of securities		13,700,000	96,300
Net loss on OTTI recognized in earnings			86,600,000
Corporate Debt Securities
Schedule of Investments [Line Items]
Net loss on OTTI recognized in earnings			10,000,000
Equity Securities
Schedule of Investments [Line Items]
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	4,200,000
Number of investment securities designated as having a continuous loss position for twelve months or more	6	7
Equity Securities | US Large Cap Equity Securities
Schedule of Investments [Line Items]
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	$ 3,600,000
Mortgage-Related Securities
Schedule of Investments [Line Items]
Number of investment securities designated as having a continuous loss position for twelve months or more	1	2
Corporate Debt Obligation
Schedule of Investments [Line Items]
Number of investment securities designated as having a continuous loss position for twelve months or more		1
Minimum
Schedule of Investments [Line Items]
Percentage of amount collected to recognize sale of securities	85.00%