Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Stock-based compensation
Stock-based compensation expense	$ 968	$ 1,607
Stock Options
Options outstanding
Outstanding at beginning of period	3,705,893
Granted in period	0
Exercised in period	0
Forfeited in period	(81,223)
Expired in period	(723,939)
Outstanding at end of period	2,900,731
Vested and expected to vest at end of period	2,900,731
Excisable at end of period	1,903,382
Weighted average exercise price
Outstanding at beginning of period	$ 7.72
Granted in period	0.00
Exercised in period	0.00
Forfeited in period	7.35
Expired in period	11.48
Outstanding at end of period	6.80
Vested and expected to vest at end of period	6.80
Exercisable at end of period	$ 8.45
Weighted average remaining contractual term
Outstanding	5 years 1 month 10 days
Vested and expected to vest	5 years 1 month 10 days
Exercisable	3 years 3 months 7 days
Additional disclosures
Unrecognized compensation costs	$ 800
Unrecognized compensation costs, recognition period	2 years 11 days
Expiration period	10 years
Stock Options | First anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Stock Options | Second anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Stock Options | Third anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Stock Options | Fourth anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Cash Stock Appreciation Rights
Outstanding
Outstanding at beginning of period	0
Granted in period	866,196
Vested in period	0
Forfeited in period	0
Outstanding at end of period	866,196
Weighted average grant date fair value
Outstanding at beginning of period	$ 0.00
Granted in period	0.97
Vested in period	0.00
Forfeited in period	0.00
Outstanding at end of period	$ 0.97
Additional disclosures
Unrecognized compensation costs	$ 500
Unrecognized compensation costs, recognition period	3 years 11 months 23 days
Cash Stock Appreciation Rights | First anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Cash Stock Appreciation Rights | Second anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Cash Stock Appreciation Rights | Third anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Cash Stock Appreciation Rights | Fourth anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Unvested Shares
Outstanding
Outstanding at beginning of period	945,252
Granted in period	948,594
Vested in period	(327,775)
Forfeited in period	(52,516)
Outstanding at end of period	1,513,555
Weighted average grant date fair value
Outstanding at beginning of period	$ 3.76
Granted in period	0.97
Vested in period	4.26
Forfeited in period	4.59
Outstanding at end of period	$ 1.87
Additional disclosures
Unrecognized compensation costs	$ 2,400
Unrecognized compensation costs, recognition period	2 years 18 days
Unvested Shares | First anniversary, vesting percentage
Additional disclosures
Vesting percentage	33.33%
Unvested Shares | Second anniversary, vesting percentage
Additional disclosures
Vesting percentage	33.33%
Unvested Shares | Third anniversary, vesting percentage
Additional disclosures
Vesting percentage	33.33%
Phantom Stock Units
Outstanding
Outstanding at beginning of period	531,820
Granted in period	560,000
Vested in period	(125,046)
Forfeited in period	(80,844)
Outstanding at end of period	885,930
Weighted average grant date fair value
Outstanding at beginning of period	$ 2.69
Granted in period	0.97
Vested in period	2.69
Forfeited in period	2.69
Outstanding at end of period	$ 1.60
Additional disclosures
Unrecognized compensation costs	$ 900
Unrecognized compensation costs, recognition period	3 years 6 months 18 days
Phantom Stock Units | Second anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Phantom Stock Units | Third anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Phantom Stock Units | Fourth anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
Performance Stock Units
Outstanding
Outstanding at beginning of period	844,315
Granted in period	288,732
Settled in period	0
Forfeited in period	(104,946)
Outstanding at end of period	1,028,101
Weighted average grant date fair value
Outstanding at beginning of period	$ 2.56
Granted in period	0.97
Vested in period	0.00
Forfeited in period	4.79
Outstanding at end of period	$ 1.88
Additional disclosures
Unrecognized compensation costs	$ 1,000
Unrecognized compensation costs, recognition period	1 year 11 months 5 days
Performance Stock Units | Minimum
Additional disclosures
Vesting percentage	0.00%
Performance Stock Units | Maximum
Additional disclosures
Vesting percentage	100.00%
Cash Performance Stock Units
Outstanding
Outstanding at beginning of period	444,005
Granted in period	0
Settled in period	0
Forfeited in period	(37,784)
Outstanding at end of period	406,221
Weighted average grant date fair value
Outstanding at beginning of period	$ 2.69
Granted in period	0.00
Vested in period	0.00
Forfeited in period	2.69
Outstanding at end of period	$ 2.69
Additional disclosures
Unrecognized compensation costs	$ 0
Cash Performance Stock Units | Minimum
Additional disclosures
Vesting percentage	0.00%
Cash Performance Stock Units | Maximum
Additional disclosures
Vesting percentage	100.00%