Investments (Summarized Financial Information of Unconsolidated Entities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Investments
Sales	$ 57,406
Total expenses	46,734
Net income	10,672
Current assets	28,318	$ 27,779
Noncurrent assets	190,100	152,112
Current liabilities	$ 18,040	$ 16,577