SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Weighted average assumptions used to determine the benefit obligation and net benefit cost
Discount rate, to determine net benefit cost (as a percent)	3.25%	3.90%
Average rate of increase in compensation, to determine net benefit cost (as a percent)	3.00%	3.00%
Change in Benefit Obligation
Net benefit cost accrued at the beginning of the period	$ 22,377	$ 20,230
Service cost	169	230
Interest cost	173	190
Payments	(705)	(525)
Net benefit cost accrued at the end of the period	$ 22,014	$ 20,125