Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
NET EARNINGS	$ 8,500	$ 6,432
OTHER COMPREHENSIVE INCOME (LOSS):
Gains and Losses on Derivatives	(8)	(9)
TOTAL OTHER COMPREHENSIVE INCOME	1,116	867
TOTAL COMPREHENSIVE INCOME	9,616	7,299
Pension Plans [Member]
OTHER COMPREHENSIVE INCOME (LOSS):
Defined Benefit Pension and Post-Retirement	1,958	1,682
Post-Retirement Plans [Member]
OTHER COMPREHENSIVE INCOME (LOSS):
Defined Benefit Pension and Post-Retirement	$ (834)	$ (806)