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Schedule I - Condensed Financial Information of the Parent (Condensed Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 61,135	$ 95,390	$ 139,855	$ 153,784
Property, plant and equipment, net	159,644us-gaap_PropertyPlantAndEquipmentNet	219,256us-gaap_PropertyPlantAndEquipmentNet
Other non-current assets	62,283us-gaap_OtherAssetsNoncurrent	69,130us-gaap_OtherAssetsNoncurrent
Total Assets	770,520us-gaap_Assets	809,956us-gaap_Assets	776,306us-gaap_Assets
LIABILITIES AND EQUITY
Current liabilities	254,681us-gaap_LiabilitiesCurrent	238,119us-gaap_LiabilitiesCurrent
Other long-term liabilities	64,919us-gaap_OtherLiabilitiesNoncurrent	59,428us-gaap_OtherLiabilitiesNoncurrent
Stockholders’ equity	211,474us-gaap_StockholdersEquity	297,780us-gaap_StockholdersEquity
Liabilities and Equity	770,520	809,956
Parent Company
ASSETS
Cash and cash equivalents	53,415	94,035	120,659	130,676
Other current assets	1,570	946
Investment in subsidiaries	197,981	242,184
Property, plant and equipment, net	1,253	1,477
Other non-current assets	8,078	5,707
Total Assets	262,297	344,349
LIABILITIES AND EQUITY
Current liabilities	7,636	12,750
Current intercompany accounts payable, net	9,756	304
Other long-term liabilities	14,732	13,065
Stockholders’ equity	211,473	297,780
Liabilities and Equity	262,297	344,349
HBB \| Parent Company
ASSETS
Investment in subsidiaries	49,613	52,265
KC \| Parent Company
ASSETS
Investment in subsidiaries	32,170	36,772
NACoal \| Parent Company
ASSETS
Investment in subsidiaries	103,056	138,355
Other \| Parent Company
ASSETS
Investment in subsidiaries	13,142	14,792
Bellaire \| Parent Company
LIABILITIES AND EQUITY
Note payable to Bellaire	$ 18,700	$ 20,450