SHAREHOLDERS' EQUITY AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income by component (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Defined benefit plans adjustment Pension	Sep. 30, 2013 Defined benefit plans adjustment Postretirement Medical Benefits	Sep. 30, 2013 Available for sale securities	Sep. 30, 2013 Tax effect of other comprehensive income gains	Dec. 31, 2012 Tax effect of other comprehensive income gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (148,345)	$ (44,717)	$ (77,527)	$ 55	$ (26,156)	$ (26,156)
Other comprehensive income before reclassifications	(43)			(43)
Amounts reclassified from accumulated other comprehensive income (loss)	5,609	2,617	3,004	(12)
Balance at end of period	$ (142,779)	$ (42,100)	$ (74,523)	$ 0	$ (26,156)	$ (26,156)