Guarantor Infromation (Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 9,832	$ 6,927
Accounts receivable - affiliates	0	0
Accounts receivable - trade	91,407	102,815
Inventories	282,270	295,462
Prepaid expenses and other current assets	24,978	21,674
Total current assets	408,487	426,878
Investment in affiliates	0	0
Net property, plant and equipment	636,962	637,533
Deferred income taxes	17,151	15,327
Goodwill	173,117	172,059
Notes receivable - affiliate	0	0
Other assets	164,823	170,218
Total assets	1,400,540	1,422,015
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	0	0
Accounts payable - trade	47,246	49,478
Short-term debt	9,779	4,772
Accrued income and other taxes	4,612	9,039
Rationalizations	1,813	3,048
Other accrued liabilities	36,950	29,779
Total current liabilities	100,400	96,116
Long-term debt - affiliate	0	0
Long-term debt - third party	360,038	362,455
Other long-term obligations	94,851	95,485
Deferred income taxes	58,460	57,430
Total stockholders' equity	786,791	810,529
Total liabilities and stockholders’ equity	1,400,540	1,422,015
Parent
ASSETS
Cash and cash equivalents	0	0
Accounts receivable - affiliates	51,592	51,592
Accounts receivable - trade	0	0
Inventories	0	0
Prepaid expenses and other current assets	0	0
Total current assets	51,592	51,592
Investment in affiliates	1,050,838	1,068,028
Net property, plant and equipment	0	0
Deferred income taxes	0	0
Goodwill	0	0
Notes receivable - affiliate	0	0
Other assets	0	0
Total assets	1,102,430	1,119,620
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	198	159
Accounts payable - trade	0	0
Short-term debt	0	0
Accrued income and other taxes	0	0
Rationalizations	0	0
Other accrued liabilities	7,225	2,444
Total current liabilities	7,423	2,603
Long-term debt - affiliate	38,826	38,661
Long-term debt - third party	269,390	267,827
Other long-term obligations	0	0
Deferred income taxes	0	0
Total stockholders' equity	786,791	810,529
Total liabilities and stockholders’ equity	1,102,430	1,119,620
Guarantors
ASSETS
Cash and cash equivalents	1,177	646
Accounts receivable - affiliates	12,055	9,362
Accounts receivable - trade	20,260	20,749
Inventories	114,633	123,340
Prepaid expenses and other current assets	7,387	8,109
Total current assets	155,512	162,206
Investment in affiliates	656,876	668,113
Net property, plant and equipment	286,386	291,494
Deferred income taxes	0	0
Goodwill	72,399	72,399
Notes receivable - affiliate	46,239	46,074
Other assets	92,017	96,964
Total assets	1,309,429	1,337,250
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	74,453	72,418
Accounts payable - trade	13,859	18,546
Short-term debt	4,636	4,636
Accrued income and other taxes	3,045	5,864
Rationalizations	638	995
Other accrued liabilities	12,268	11,511
Total current liabilities	108,899	113,970
Long-term debt - affiliate	0	0
Long-term debt - third party	89,723	93,758
Other long-term obligations	59,720	61,246
Deferred income taxes	249	248
Total stockholders' equity	1,050,838	1,068,028
Total liabilities and stockholders’ equity	1,309,429	1,337,250
Non-Guarantors
ASSETS
Cash and cash equivalents	8,655	6,281
Accounts receivable - affiliates	22,855	20,823
Accounts receivable - trade	71,147	82,066
Inventories	167,637	172,122
Prepaid expenses and other current assets	17,591	13,565
Total current assets	287,885	294,857
Investment in affiliates	0	0
Net property, plant and equipment	350,576	346,039
Deferred income taxes	17,151	15,327
Goodwill	100,718	99,660
Notes receivable - affiliate	0	0
Other assets	72,806	73,254
Total assets	829,136	829,137
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	11,851	9,200
Accounts payable - trade	33,387	30,932
Short-term debt	5,143	136
Accrued income and other taxes	1,567	3,175
Rationalizations	1,175	2,053
Other accrued liabilities	17,457	15,824
Total current liabilities	70,580	61,320
Long-term debt - affiliate	7,413	7,413
Long-term debt - third party	925	870
Other long-term obligations	35,131	34,239
Deferred income taxes	58,211	57,182
Total stockholders' equity	656,876	668,113
Total liabilities and stockholders’ equity	829,136	829,137
Consolidating Entries and Eliminations
ASSETS
Cash and cash equivalents	0	0
Accounts receivable - affiliates	(86,502)	(81,777)
Accounts receivable - trade	0	0
Inventories	0	0
Prepaid expenses and other current assets	0	0
Total current assets	(86,502)	(81,777)
Investment in affiliates	(1,707,714)	(1,736,141)
Net property, plant and equipment	0	0
Deferred income taxes	0	0
Goodwill	0	0
Notes receivable - affiliate	(46,239)	(46,074)
Other assets	0	0
Total assets	(1,840,455)	(1,863,992)
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable - affiliate	(86,502)	(81,777)
Accounts payable - trade	0	0
Short-term debt	0	0
Accrued income and other taxes	0	0
Rationalizations	0	0
Other accrued liabilities	0	0
Total current liabilities	(86,502)	(81,777)
Long-term debt - affiliate	(46,239)	(46,074)
Long-term debt - third party	0	0
Other long-term obligations	0	0
Deferred income taxes	0	0
Total stockholders' equity	(1,707,714)	(1,736,141)
Total liabilities and stockholders’ equity	$ (1,840,455)	$ (1,863,992)