Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Stock-based compensation
Stock-based compensation expense	$ 1,818	$ 2,373
Stock Options
Options outstanding
Outstanding at beginning of period	3,705,893
Granted in period	0
Exercised in period	0
Forfeited in period	(89,630)
Expired in period	(847,898)
Outstanding at end of period	2,768,365
Vested and expected to vest at end of period	2,768,365
Excisable at end of period	2,003,764
Weighted average exercise price
Outstanding at beginning of period	$ 7.72
Granted in period	0.00
Exercised in period	0.00
Forfeited in period	7.13
Expired in period	11.07
Outstanding at end of period	6.72
Vested and expected to vest at end of period	6.72
Exercisable at end of period	$ 7.59
Weighted average remaining contractual term
Outstanding	5 years 1 month 6 days
Vested and expected to vest	5 years 1 month 6 days
Exercisable	3 years 8 months 23 days
Additional disclosures
Unrecognized compensation costs	$ 700
Unrecognized compensation costs, recognition period	1 year 9 months 26 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 8 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	1,336,060
Vested in period	(405,241)
Forfeited in period	(132,468)
Outstanding at end of period	1,743,603
Weighted average grant date fair value
Outstanding at beginning of period	$ 3.76
Granted in period	0.98
Vested in period	4.13
Forfeited in period	2.76
Outstanding at end of period	$ 1.61
Additional disclosures
Unrecognized compensation costs	$ 2,300
Unrecognized compensation costs, recognition period	1 year 11 months 16 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	(112,360)
Outstanding at end of period	854,414
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	2.51
Outstanding at end of period	$ 1.59
Additional disclosures
Unrecognized compensation costs	$ 800
Unrecognized compensation costs, recognition period	3 years 3 months 26 days
Phantom Stock Units | First anniversary, vesting percentage
Additional disclosures
Vesting percentage	25.00%
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	711,268
Settled in period	0
Forfeited in period	(104,946)
Outstanding at end of period	1,450,637
Weighted average grant date fair value
Outstanding at beginning of period	$ 2.56
Granted in period	0.99
Vested in period	0.00
Forfeited in period	4.79
Outstanding at end of period	$ 1.63
Additional disclosures
Unrecognized compensation costs	$ 1,300
Unrecognized compensation costs, recognition period	1 year 10 months 24 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	1,098,871
Settled in period	0
Forfeited in period	(37,784)
Outstanding at end of period	1,505,092
Weighted average grant date fair value
Outstanding at beginning of period	$ 2.69
Granted in period	1.01
Vested in period	0.00
Forfeited in period	2.69
Outstanding at end of period	$ 1.46
Additional disclosures
Unrecognized compensation costs	$ 1,100
Cash Performance Stock Units | Minimum
Additional disclosures
Vesting percentage	0.00%
Cash Performance Stock Units | Maximum
Additional disclosures
Vesting percentage	100.00%