Related Party Transactions (Affiliated Notes Receivable) (Details) - Affiliated Entity - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Total long-term notes receivable - affiliated	$ 137,727	$ 137,636
U.S. Dollar floating rate notes
Related Party Transaction [Line Items]
Total long-term notes receivable - affiliated	$ 6,556	0
U.S. Dollar floating rate notes | Minimum
Related Party Transaction [Line Items]
Interest Rates	2.73%
U.S. Dollar floating rate notes | Maximum
Related Party Transaction [Line Items]
Interest Rates	2.76%
U.S. Dollar fixed rate notes
Related Party Transaction [Line Items]
Total long-term notes receivable - affiliated	$ 131,171	$ 137,636
U.S. Dollar fixed rate notes | Minimum
Related Party Transaction [Line Items]
Interest Rates	0.00%
U.S. Dollar fixed rate notes | Maximum
Related Party Transaction [Line Items]
Interest Rates	14.85%