SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Weighted average assumptions used to determine the benefit obligation and net benefit cost
Discount rate, to determine the benefit obligation (as a percent)	3.90%
Average rate of increase in compensation, to determine the benefit obligation (as a percent)	3.00%
Discount rate, to determine net benefit cost (as a percent)	3.90%
Average rate of increase in compensation, to determine net benefit cost (as a percent)	3.00%
Change in Benefit Obligation
Net benefit cost accrued at the beginning of the period	$ 20,230	$ 17,510
Service cost	230	247
Interest cost	190	202
Payments	(525)
Net benefit cost accrued at the end of the period	$ 20,125	$ 17,959