Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Interest paid	$ 12,430	$ 9,567
Taxes paid	0	0
Noncash investing and financing activity
Capital projects incurred but not yet paid	3,695	9,653
Investment merger (decreasing equity method investments and non-controlling interest)	8,360	0
Outstanding receivable for sale of assets	4,356	0
Dividends declared not yet paid	$ 4,501	$ 4,341