SHAREHOLDERS' EQUITY, DIVIDEND RESTRICTIONS AND OTHER REGULATORY MATTERS (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%
Leverage Capital Required Ratio To Tangible Assets	3.00%
Percent Of Trust Preferred Securities Excluded From Tier One Starting In 2013	33.33%
Trust Preferred Securities	$ 93,500,000
Proforma Tier 1 Leverage Ratio	8.78%
Proforma Tier 1 Risk Based Ratio	13.59%
Proforma Total Risk Based Ratio	15.27%
Tier 2 capital	50,000,000	75,000,000
Tier 2 capital, subordinated debt eligibility reduction, 2013	25,000,000
Tier 2 capital, subordinated debt eligibility reduction, 2014	25,000,000
Amount Available for Dividend Distribution without Prior Approval from Regulatory Agency	1,382,080,000
Maximum Undivided Profits Elgible For Dividend Payment Without Changing Well Capitalized Status	809,000,000
Dividends, Common Stock, Cash	179,588,000	82,812,000	50,424,000
Average Required Maintence Of Non Interst Bearing Reserve Balance	290,968,000
Common Class A [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchased During Period, Shares	56,276	112,471
Common Class B [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchased and Retired During Period, Shares	606,829
Stock Repurchased During Period, Shares	606,929	37,863
Common Class B [Member] | Majority Shareholder [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchased and Retired During Period, Shares	593,954
BancShares [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital for Capital Adequacy	1,949,985,000	2,072,610,000
Capital Required for Capital Adequacy	2,179,370,000	2,323,022,000
Leverage Capital Required for Capital Adequacy	1,949,985,000	2,072,610,000
Tier 1 Risk Based Capital to Risk Weighted Assets	14.27%	15.41%
Capital to Risk Weighted Assets	15.95%	17.27%
Leverage Capital to Average Assets	9.22%	9.90%
Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.00%	6.00%
Capital Required to be Well Capitalized	10.00%	10.00%
Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
FCB [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital for Capital Adequacy	1,942,101,000	1,968,032,000
Capital Required for Capital Adequacy	2,163,034,000	2,211,235,000
Leverage Capital Required for Capital Adequacy	$ 1,942,101,000	$ 1,968,032,000
Tier 1 Risk Based Capital to Risk Weighted Assets	14.37%	14.75%
Capital to Risk Weighted Assets	16.00%	16.57%
Leverage Capital to Average Assets	9.34%	9.53%
Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.00%	6.00%
Capital Required to be Well Capitalized	10.00%	10.00%
Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Board Authority, Share Repurchase Program [Member] | Common Class A [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	100,000
Stock Repurchased During Period, Shares	56,276
Stock Repurchase Program, Number of Shares Under Regulatory Authorization to be Repurchased	43,724
Board Authority, Share Repurchase Program [Member] | Common Class B [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	25,000
Stock Repurchased During Period, Shares	100
Stock Repurchase Program, Number of Shares Under Regulatory Authorization to be Repurchased	24,900