CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
NET INCOME	$ 82,844	$ 49,435	$ 150,978	$ 98,952
Pension and other postretirement benefit adjustments, net of income taxes of $1,969 and $1,825 for the three months ended June 30, 2013 and 2012, and $3,922 and $3,650 for the six months ended June 30, 2013 and 2012, respectively:
Amortization of net loss	4,447	4,087	8,859	8,174
Amortization of transition obligation	0	77	0	154
Amortization of prior service cost	(790)	(776)	(1,574)	(1,551)
Total other comprehensive income	3,657	3,388	7,285	6,777
COMPREHENSIVE INCOME	$ 86,501	$ 52,823	$ 158,263	$ 105,729