INVESTMENT SECURITIES (Details 2) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 First California Financial Group	May 31, 2013 First California Financial Group	Jun. 30, 2013 Government agency and government-sponsored enterprise pass through securities	Dec. 31, 2012 Government agency and government-sponsored enterprise pass through securities	Jun. 30, 2013 Government agency and government-sponsored enterprise collateralized mortgage obligations	Dec. 31, 2012 Government agency and government-sponsored enterprise collateralized mortgage obligations	Jun. 30, 2013 Covered private label collateralized mortgage obligations	Dec. 31, 2012 Covered private label collateralized mortgage obligations	Jun. 30, 2013 Municipal securities	Dec. 31, 2012 Municipal securities	Jun. 30, 2013 Corporate debt securities	Dec. 31, 2012 Corporate debt securities	Jun. 30, 2013 Other securities	Dec. 31, 2012 Other securities
Amortized Cost
Due in one year or less	$ 4,696,000			$ 4,696,000
Due after one year through five years	24,214,000			24,214,000
Due after five years through ten years	107,766,000			107,766,000
Due after ten years	1,335,186,000			1,335,186,000
Total securities available-for-sale	1,471,862,000			1,471,862,000		1,298,661,000			726,501,000	774,677,000	147,580,000	99,956,000	32,959,000	36,078,000	442,733,000	339,547,000	83,938,000	42,014,000	38,151,000	6,389,000
Carrying Value
Due in one year or less	4,813,000			4,813,000
Due after one year through five years	24,219,000			24,219,000
Due after five years through ten years	106,582,000			106,582,000
Due after ten years	1,337,964,000			1,337,964,000
Carrying Value	1,473,578,000			1,473,578,000		1,355,385,000			742,417,000	807,842,000	145,320,000	101,694,000	40,917,000	44,684,000	424,174,000	348,041,000	83,132,000	42,365,000	37,618,000	10,759,000
Estimated fair value of available-for-sale securities pledged as collateral	208,200,000			208,200,000
Carrying values and gross unrealized losses on securities by length of time the securities were in an unrealized loss position
Less Than 12 Months, Carrying Value	627,715,000			627,715,000		192,738,000			128,542,000	67,299,000	100,267,000	18,317,000	602,000		302,174,000	90,303,000	72,146,000	16,819,000	23,984,000
Less Than 12 Months, Gross Unrealized Losses	(27,181,000)			(27,181,000)		(2,616,000)			(1,691,000)	(452,000)	(2,979,000)	(132,000)	(31,000)		(20,953,000)	(1,951,000)	(993,000)	(81,000)	(534,000)
12 months or Longer, Carrying Value	2,154,000			2,154,000		1,752,000			53,000	60,000	1,436,000		665,000	1,692,000
12 months or Longer, Gross Unrealized Losses	(109,000)			(109,000)		(124,000)			(1,000)	(1,000)	(3,000)		(105,000)	(123,000)
Total, Carrying Value	629,869,000			629,869,000		194,490,000			128,595,000	67,359,000	101,703,000	18,317,000	1,267,000	1,692,000	302,174,000	90,303,000	72,146,000	16,819,000	23,984,000
Total, Gross Unrealized Losses	(27,290,000)			(27,290,000)		(2,740,000)			(1,692,000)	(453,000)	(2,982,000)	(132,000)	(136,000)	(123,000)	(20,953,000)	(1,951,000)	(993,000)	(81,000)	(534,000)
FHLB stock							9,500,000	9,518,000
Interest income on investment securities
Taxable interest	5,388,000	5,563,000	8,365,000	10,951,000	16,904,000
Nontaxable interest	2,716,000	2,425,000	1,134,000	5,141,000	2,114,000
Dividend income	310,000	228,000	59,000	538,000	120,000
Total interest income on investment securities	8,414,000	8,216,000	9,558,000	16,630,000	19,138,000
FHLB Stock
Investment in Federal Home Loan Bank stock carried at cost	39,129,000			39,129,000		37,126,000
Increase in FHLB stock	5,700,000
Net redemptions of FHLB stock	$ 3,800,000