INCOME TAXES (Effective Income Tax Rate Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Provision for (benefit from) income taxes computed at federal statutory rate													$ 24,179	$ 14,034	$ 1,910
Increase (decrease) in taxes due to:
Tax-exempt interest													(1,633)	(1,710)	(1,616)
Investment in life insurance													(707)	(894)	(663)
State income taxes (benefit), net of federal tax offset													824	539	(2,260)
Tax credits													(636)	(788)	(840)
Valuation allowance													0	(36,385)	3,322
Other													501	419	147
Provision for (benefit from) income taxes	$ 5,704	$ 5,880	$ 5,661	$ 5,284	$ 4,638	$ 2,407	$ (31,830)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 22,528	$ (24,785)	$ 0
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal income tax statutory rate													35.00%	35.00%	35.00%
Increase (decrease) in tax rate due to:
Tax-exempt interest													(2.40%)	(4.30%)	(29.60%)
Investment in life insurance													(1.00%)	(2.20%)	(12.10%)
State income taxes (benefit), net of federal tax offset													1.20%	1.30%	(41.50%)
Tax credits													(0.90%)	(2.00%)	(15.40%)
Valuation allowance													0.00%	(90.70%)	60.90%
Other													0.70%	1.10%	2.70%
Effective income tax rate													32.60%	(61.80%)	0.00%