Derivative Financial Instruments (Narrative) (Details)			12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 Foreign exchange contract USD ($)	Dec. 31, 2014 Foreign exchange contract CAD	Dec. 31, 2013 Foreign exchange contract USD ($)	Dec. 31, 2013 Foreign exchange contract CAD	Dec. 31, 2014 Interest rate contract HBB USD ($)	Dec. 31, 2013 Interest rate contract HBB USD ($)	Dec. 31, 2014 Interest rate contract NACoal USD ($)	Dec. 31, 2013 Interest rate contract NACoal USD ($)
Derivative [Line Items]
Interest rate derivative assets, at fair value	$ 181,000	$ 937,000					$ 200,000	$ 800,000
Interest rate derivative liabilities, at fair value	412,000								400,000
Notional amount of foreign currency derivatives				7,200,000		5,000,000	20,000,000	20,000,000	100,000,000	100,000,000
Derivative, fair value, net			300,000		(100,000)
Cash flow hedge gain (loss) to be reclassified within twelve months			100,000
Interest rate cash flow hedge gain (loss) to be reclassified during next twelve months							$ 100,000		$ 800,000