Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Income Statement [Abstract]
Net sales	$ 1,518,940		$ 845,440		$ 4,418,653		$ 2,400,877
Cost of sales	(1,198,607)		(617,841)		(3,486,108)		(1,792,782)
Gross profit	320,333		227,599		932,545		608,095
Selling, general, and administrative expenses	(119,645)		(77,096)		(359,007)		(226,606)
Other expense, net	(12,310)		(7,721)		(44,004)		(22,510)
Income from operations	188,378	[1]	142,782		529,534	[1]	358,979
Interest expense, net	(23,111)	[1],[2]	(11,850)	[3]	(65,311)	[1],[2]	(30,333)	[3]
Income before taxes	165,267	[1]	130,932		464,223	[1]	328,646
Income tax provision	(60,822)		(46,250)		(170,135)		(115,418)
Net income	104,445		84,682		294,088		213,228
Net income per common share:
Basic (in dollars per share)	$ 1.06		$ 0.88		$ 2.99		$ 2.21
Diluted (in dollars per share)	$ 1.06		$ 0.87		$ 2.99		$ 2.19
Dividends declared per common share	$ 0.40		$ 0.40		$ 1.20		$ 1.11
Statements of Comprehensive Income:
Net income	104,445		84,682		294,088		213,228
Foreign currency translation adjustment, net of tax of ($106), $0, ($76), and $0, respectively	(1,564)		0		(1,656)		0
Reclassification adjustments to cash flow hedges included in net income, net of tax of $553, $552, $1,668, and $1,658, respectively	870		870		2,599		2,609
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of $685, $2,153, $2,157, and $7,574, respectively	1,080		3,387		3,137		11,921
Changes in unfunded employee benefit obligation, net of tax of $0, $3,152, $0, and $8,522, respectively	0		4,963		0		13,418
Other comprehensive income	386		9,220		4,080		27,948
Comprehensive income	$ 104,831		$ 93,902		$ 298,168		$ 241,176

[1] On October 25, 2013, we acquired Boise. The 2014 results include Boise for the full period.

[2] Includes $1.5 million of expense related to the write-off of deferred financing costs in connection with the debt refinancing discussed in Note 10, Debt.

[3] Includes $2.7 million of acquisition-related costs primarily related to financing the acquisition of Boise.