Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
NET EARNINGS (LOSS)	$ (19,628)	$ 40,874	$ 23,192
Other comprehensive income (loss), net of tax	(29)	(37)	2,745
OTHER COMPREHENSIVE INCOME (LOSS):
Actuarial gain (loss) for retiree liabilities	130,330	(27,350)	(91,523)
Unrealized gain (loss) for derivative instruments			631
Income tax (expense) or benefit	21	20	(1,595)
TOTAL COMPREHENSIVE INCOME (LOSS), net of tax	67,841	26,634	(33,621)
Pension Plans [Member]
Other comprehensive income (loss), net of tax	90,530	(10,976)	(56,301)
OTHER COMPREHENSIVE INCOME (LOSS):
Actuarial gain (loss) for retiree liabilities	129,856	(27,518)	(91,715)
Income tax (expense) or benefit	(51,622)	5,861	32,714
Post-Retirement Plans [Member]
Other comprehensive income (loss), net of tax	(3,032)	(3,227)	(3,257)
OTHER COMPREHENSIVE INCOME (LOSS):
Actuarial gain (loss) for retiree liabilities	474	168	192
Income tax (expense) or benefit	$ 1,729	$ 1,724	$ 1,892