Selling Arrangement - Carrying Amount (Details) - Customer Contracts [Member] - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross cost	$ 4,000,000	$ 4,000,000
Accumulated amortization	(2,283,000)	(1,883,000)
Net carrying amount	$ 1,717,000	$ 2,117,000