Fair Value Measurements (Fair Value of Other Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrowings under revolving credit facility	$ 27,950	$ 38,566
Carrying Amount | Term loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Term loan	0	9,833
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrowings under revolving credit facility	27,950	38,566
Fair Value | Term loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Term loan	$ 0	$ 9,833