Debt Revolving Credit Agreement (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Class of Warrant or Right, Outstanding	5,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 100,000	$ 125,000
Line of Credit Facility, Availability Block, Initial Amount				17,500
Redemption Permitted, New Secured Notes, Amount				27,500
Redemption Permitted, Secured Notes, Amount				6,000
Debt Instrument, Interest Rate During Period	3.65%	2.70%	3.08%
Debt Instrument, Maturity Date	Dec. 10, 2019
CANADA | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				16,000	20,000
Letter of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 16,000	$ 20,000