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Long-Term Compensation Plan and Stock Based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Long-Term Compensation Plan and Stock Based Compensation
Unissued shares	35,000
Restricted Stock, subject to performance criteria
Long-Term Compensation Plan and Stock Based Compensation
Unissued shares			161,000
Restricted Stock, subject to time-based criteria
Long-Term Compensation Plan and Stock Based Compensation
Stock based compensation awards issued shares			163,000
Unissued shares	34,000
2009 Equity Incentive Plan
Long-Term Compensation Plan and Stock Based Compensation
Stock based compensation awards issued shares	0
2009 Equity Incentive Plan \| Restricted Stock
Long-Term Compensation Plan and Stock Based Compensation
Stock based compensation Awards	69		324
Stock issues during the period		0
2009 Equity Incentive Plan \| Restricted Stock, subject to performance criteria
Long-Term Compensation Plan and Stock Based Compensation
Unissued shares	35,000		161,000
Vesting period (in years)	3 years		3 years
Fair value of nonvested awards	$ 0.6		$ 2.3
2009 Equity Incentive Plan \| Restricted Stock, subject to time-based criteria
Long-Term Compensation Plan and Stock Based Compensation
Stock based compensation awards issued shares	34,000		163,000
Restricted stock awards, fair value	$ 0.6		$ 2.3
2009 Equity Incentive Plan \| Restricted Stock, subject to time-based criteria \| Minimum
Long-Term Compensation Plan and Stock Based Compensation
Vesting period (in years)	1 year		1 year
2009 Equity Incentive Plan \| Restricted Stock, subject to time-based criteria \| Maximum
Long-Term Compensation Plan and Stock Based Compensation
Vesting period (in years)	4 years		4 years