Supplemental Guarantor Infromation Supplemental Guarantor Information (Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 10,986	$ 17,317	$ 7,137	$ 7,137	$ 12,429
Accounts receivable - affiliates	0	0
Accounts receivable - trade	206,661	236,429
Inventories	540,773	513,065
Prepaid expenses and other current assets	73,271	56,190
Total current assets	831,691	823,001
Investment in affiliates	0	0
Property, plant and equipment	836,676	833,907
Deferred income taxes	6,112	6,157
Goodwill	497,162	498,261
Notes receivable - affiliate	0	0
Other assets	124,577	136,589
Total assets	2,296,218	2,297,915
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	0	0
Accounts payable - trade	111,379	128,120
Short-term debt	2,777	8,426
Accrued income and other taxes	28,047	30,923
Supply chain financing liability	18,594	26,962
Other accrued liabilities	50,301	50,953
Total current liabilities	211,098	245,384
Long-term debt - affiliate	0	0
Long-term debt - third party	581,723	535,709
Other long-term obligations	117,432	125,005
Deferred income taxes	38,904	41,966
Total stockholders' equity	1,347,061	1,349,851
Total liabilities and stockholders' equity	2,296,218	2,297,915
Parent Company [Member]
ASSETS
Cash and cash equivalents	0	0		0	366
Accounts receivable - affiliates	35,702	26,399
Accounts receivable - trade	0	0
Inventories	0	0
Prepaid expenses and other current assets	0	0
Total current assets	35,702	26,399
Investment in affiliates	1,729,881	1,728,316
Property, plant and equipment	0	0
Deferred income taxes	0	0
Goodwill	0	0
Notes receivable - affiliate	59,303	66,869
Other assets	5,040	5,218
Total assets	1,829,926	1,826,802
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	0	0
Accounts payable - trade	51	273
Short-term debt	0	0
Accrued income and other taxes	818	597
Supply chain financing liability	0	0
Other accrued liabilities	2,444	2,178
Total current liabilities	3,313	3,048
Long-term debt - affiliate	0	0
Long-term debt - third party	469,832	464,183
Other long-term obligations	0	0
Deferred income taxes	9,720	9,720
Total stockholders' equity	1,347,061	1,349,851
Total liabilities and stockholders' equity	1,829,926	1,826,802
Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	3,992	4,425		3,242	3,503
Accounts receivable - affiliates	30,259	38,116
Accounts receivable - trade	71,634	78,053
Inventories	176,778	159,217
Prepaid expenses and other current assets	30,518	13,681
Total current assets	313,181	293,492
Investment in affiliates	858,788	868,063
Property, plant and equipment	532,739	523,818
Deferred income taxes	0	0
Goodwill	293,162	293,162
Notes receivable - affiliate	22,413	22,413
Other assets	58,763	65,269
Total assets	2,079,046	2,066,217
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	57,754	55,349
Accounts payable - trade	35,642	33,126
Short-term debt	174	171
Accrued income and other taxes	1,916	3,948
Supply chain financing liability	0	0
Other accrued liabilities	17,822	15,597
Total current liabilities	113,308	108,191
Long-term debt - affiliate	59,303	66,869
Long-term debt - third party	88,602	70,190
Other long-term obligations	81,453	86,026
Deferred income taxes	6,499	6,625
Total stockholders' equity	1,729,881	1,728,316
Total liabilities and stockholders' equity	2,079,046	2,066,217
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	6,994	12,892		3,895	8,560
Accounts receivable - affiliates	22,052	29,177
Accounts receivable - trade	135,027	158,376
Inventories	363,995	353,848
Prepaid expenses and other current assets	42,753	42,509
Total current assets	570,821	596,802
Investment in affiliates	0	0
Property, plant and equipment	303,937	310,089
Deferred income taxes	6,112	6,157
Goodwill	204,000	205,099
Notes receivable - affiliate	0	0
Other assets	60,774	66,102
Total assets	1,145,644	1,184,249
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	30,259	38,343
Accounts payable - trade	75,686	94,721
Short-term debt	2,603	8,255
Accrued income and other taxes	25,313	26,378
Supply chain financing liability	18,594	26,962
Other accrued liabilities	30,035	33,178
Total current liabilities	182,490	227,837
Long-term debt - affiliate	22,413	22,413
Long-term debt - third party	23,289	1,336
Other long-term obligations	35,979	38,979
Deferred income taxes	22,685	25,621
Total stockholders' equity	858,788	868,063
Total liabilities and stockholders' equity	1,145,644	1,184,249
Consolidating Entries and Eliminations [Member]
ASSETS
Cash and cash equivalents	0	0		0	0
Accounts receivable - affiliates	(88,013)	(93,692)
Accounts receivable - trade	0	0
Inventories	0	0
Prepaid expenses and other current assets	0	0
Total current assets	(88,013)	(93,692)
Investment in affiliates	(2,588,669)	(2,596,379)
Property, plant and equipment	0	0
Deferred income taxes	0	0
Goodwill	0	0
Notes receivable - affiliate	(81,716)	(89,282)
Other assets	0	0
Total assets	(2,758,398)	(2,779,353)
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	(88,013)	(93,692)
Accounts payable - trade	0	0
Short-term debt	0	0
Accrued income and other taxes	0	0
Supply chain financing liability	0	0
Other accrued liabilities	0	0
Total current liabilities	(88,013)	(93,692)
Long-term debt - affiliate	(81,716)	(89,282)
Long-term debt - third party	0	0
Other long-term obligations	0	0
Deferred income taxes	0	0
Total stockholders' equity	(2,588,669)	(2,596,379)
Total liabilities and stockholders' equity	$ (2,758,398)	$ (2,779,353)