Stock-Based Compensation - Stock Options Activity (Details) - Stock options $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares shares
Stock Options
Options outstanding at the beginning of the period (in shares) | shares	489
Cancelled (in shares) | shares	(53)
Options outstanding at the end of the period (in shares) | shares	436
Options exercisable at the end of the period (in shares) | shares	436
Weighted Average Exercise Price Per Share
Options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 12.28
Cancelled (in dollars per share) | $ / shares	13.96
Options outstanding at end of period, (in dollars per share) | $ / shares	12.07
Options exercisable at the end of period (in dollars per share) | $ / shares	$ 12.07
Weighted Average Remaining Life
Outstanding at the end of the period	1 year 5 months 1 day
Exercisable at the end of the period	1 year 5 months 1 day
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars) | $	$ 548
Exercisable at the end of the period (in dollars) | $	$ 548