CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net Income	$ 5,704	$ 20,954	$ 20,749
Portion reclassified through amortizations, included in benefit costs and recognized in net income:
Actuarial losses, net of income taxes of $65 in 2011, $1 in 2010 and $2 in 2009	96	2	3
Prior service cost, net of income taxes of $(1) in 2011, $(1) in 2010 and $9 in 2009	(2)	(2)	14
Change in funded status of pension, postretirement medical and other benefit plans, net of income taxes of $(33) in 2011, $(16) in 2010 and $2 in 2009	(48)	(23)	2
Comprehensive income adjustments	46	(23)	19
Total comprehensive income	$ 5,750	$ 20,931	$ 20,768