CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 46,002	$ 79,000	$ 107,073	$ 164,386
Other comprehensive income, net of tax:
Prior service cost amortization, net of income tax of $152, $135, $303 and $270	(237)	(211)	(474)	(422)
Net actuarial pension loss amortization, net of income tax of $259, $186, $531 and $372	404	290	827	580
Unrealized gains (losses) on available-for-sale securities, net of income tax of $0, $0, $0 and $0	2	46	(21)	(87)
Other comprehensive income, net of tax	169	125	332	71
Comprehensive income	$ 46,171	$ 79,125	$ 107,405	$ 164,457