Accounting Policies - Investments in Affiliated Companies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Revenue		$ 9,088	$ 89,157
Gross profit		3,489	27,336
Net income		2,413	17,946
Equity in earnings of affiliated companies	$ 0	$ 570	$ 5,159