Stockholders' Equity - Changes in Stockholder's Equity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 96,926	$ 128,688	$ 120,065	$ 109,596	$ 128,688	$ 109,596
Beginning balance (in shares)		30,801,255			30,801,255
Share-based compensation expense	854	$ 862			$ 1,716
Share-based compensation expense			719	761
Total comprehensive loss	$ (9,919)	(32,624)	8,101	9,780	$ (42,543)	17,881
Ending balance (in shares)	30,985,669				30,985,669
Ending balance	$ 87,861	96,926	128,885	120,065	$ 87,861	128,885	$ 109,596
Accounting Standards Update [Extensible List]							us-gaap:AccountingStandardsUpdate201602Member
Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance				(72)		(72)
Ending balance							$ (72)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 323	$ 323	$ 318	$ 318	$ 323	$ 318
Beginning balance (in shares)	30,847,000	30,801,000	30,513,000	30,513,000	30,801,000	30,513,000
Share-based compensation expense					$ (14)
Share-based compensation expense (in shares)	138,000	46,000	68,000		184,000
Share-based compensation expense			$ 1
Ending balance (in shares)	30,985,000	30,847,000	30,581,000	30,513,000	30,985,000	30,581,000	30,513,000
Ending balance	$ 309	$ 323	$ 319	$ 318	$ 309	$ 319	$ 318
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(11,230)	(11,230)	(10,245)	(10,245)	(11,230)	(10,245)
Ending balance	(11,230)	(11,230)	(10,245)	(10,245)	(11,230)	(10,245)	(10,245)
Additional Paid In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	246,714	245,852	243,768	243,007	245,852	243,007
Share-based compensation expense	868	862			1,730
Share-based compensation expense			718	761
Ending balance	247,582	246,714	244,486	243,768	247,582	244,486	243,007
Retained Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(84,901)	(60,307)	(66,099)	(76,013)	(60,307)	(76,013)
Total comprehensive loss	(12,497)	(24,594)	6,146	9,986	(37,091)
Ending balance	(97,398)	(84,901)	(59,953)	(66,099)	(97,398)	(59,953)	(76,013)
Retained Deficit | Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance				(72)		(72)
Ending balance							(72)
Accumulated  Other Comp. Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(53,980)	(45,950)	(47,677)	(47,471)	(45,950)	(47,471)
Total comprehensive loss	2,578	(8,030)	1,955	(206)	(5,452)
Ending balance	$ (51,402)	$ (53,980)	$ (45,722)	$ (47,677)	$ (51,402)	$ (45,722)	$ (47,471)