Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 161,991	$ 190,960
Accounts receivable, net of allowance for doubtful accounts and customer deductions of $11,712 and $10,567 as of June 30, 2014, and December 31, 2013, respectively	704,218	643,083
Inventories	611,342	594,291
Prepaid expenses and other current assets	59,737	32,101
Federal and state income taxes receivable	2,870	22,958
Deferred income taxes	34,091	47,616
Total current assets	1,574,249	1,531,009
Property, plant, and equipment, net	2,817,249	2,805,704
Goodwill	537,363	526,789
Intangible assets, net	306,002	310,539
Other long-term assets	69,374	69,738
Total assets	5,304,237	5,243,779
Current liabilities:
Current maturities of long-term debt	6,500	39,000
Capital lease obligations	1,065	1,030
Accounts payable	394,743	357,432
Dividends payable	39,359	39,297
Accrued liabilities	207,314	214,058
Accrued interest	8,932	9,722
Total current liabilities	657,913	660,539
Long-term liabilities:
Long-term debt	2,425,441	2,508,845
Capital lease obligations	23,333	23,874
Deferred income taxes	430,947	434,835
Pension and postretirement benefit plans	200,900	193,548
Other long-term liabilities	83,084	65,318
Total long-term liabilities	3,163,705	3,226,420
Commitments and contingent liabilities
Stockholders' equity:
Common stock, par value $0.01 per share, 300,000 shares authorized, 98,389 and 98,172 shares issued as of June 30, 2014, and December 31, 2013, respectively	984	982
Additional paid in capital	423,598	401,761
Retained earnings	1,119,367	1,019,101
Accumulated other comprehensive loss	(61,330)	(65,024)
Total stockholders' equity	1,482,619	1,356,820
Total liabilities and stockholders' equity	$ 5,304,237	$ 5,243,779