Debt Schedule of Long-Term Debt Repayments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 29,063	$ 79,119	$ 62,998
Line of Credit [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	15,000	67,869	49,873
USD Denominated Term Loan [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	14,063	11,250	13,125
Secured Debt [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 29,063	$ 79,119	$ 62,998