Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current deferred tax assets
Provisions not currently deductible	$ 0	$ 7,234
Tax credits and other	0	246
Net operating loss —state	0	208
Total current deferred tax asset	0	7,688
Non-current deferred tax assets
Provisions not currently deductible	8,192	392
Stock based compensation	110	136
Net operating loss carryforwards—federal and state	173	0
Net capital loss carryforwards—federal and state	1,859	1,859
Deferred Tax Assets, Tax Credit Carryforwards, Other	519	0
Pensions and post retirement	3,223	3,095
Deferred Tax Assets, Gross, Noncurrent	14,076	5,482
Total deferred tax asset	14,076	13,170
Non-current deferred tax liabilities
Investment in joint ventures/partnerships	(2,056)	(2,269)
Property, plant and equipment	(234,358)	(171,562)
Total deferred tax liability	$ (236,414)	$ (173,831)