Parent Company Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 52,499	$ 61,135	$ 95,390	$ 139,855
Property, plant and equipment, net	132,539	159,644
Other non-current assets	56,326	62,283
Total assets	655,408	770,520	809,956
LIABILITIES AND EQUITY
Current liabilities	191,746	254,681
Other long-term liabilities	52,585	64,919
Stockholders’ equity	201,138	211,474
Total Liabilities and Stockholders’ Equity	655,408	770,520
Parent Company
ASSETS
Cash and cash equivalents	22,506	53,415	$ 94,035	$ 120,659
Current intercompany accounts receivable, net	2,555	0
Other current assets	1,241	1,570
Investment in subsidiaries	205,024	197,982
Property, plant and equipment, net	1,276	1,253
Other non-current assets	8,534	8,078
Total assets	241,136	262,298
LIABILITIES AND EQUITY
Current liabilities	6,323	7,636
Current intercompany accounts payable, net	0	9,756
Other long-term liabilities	14,975	14,732
Stockholders’ equity	201,138	211,474
Total Liabilities and Stockholders’ Equity	241,136	262,298
Restricted investments	182,100
Unrestricted investment	12,000
HBB | Parent Company
ASSETS
Investment in subsidiaries	51,377	49,613
KC | Parent Company
ASSETS
Investment in subsidiaries	31,750	32,170
NACoal | Parent Company
ASSETS
Investment in subsidiaries	108,381	103,056
Other | Parent Company
ASSETS
Investment in subsidiaries	13,516	13,143
Bellaire | Parent Company
LIABILITIES AND EQUITY
Note payable to Bellaire	$ 18,700	$ 18,700