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Stock-Based and Other Long-Term Incentive Compensation - Restricted Stock Narrative (Details) - Restricted Stock $ in Millions				12 Months Ended
	Apr. 28, 2021	Apr. 28, 2020 shares	Jun. 18, 2014 shares	Dec. 31, 2020 USD ($) independent_director shares	Dec. 31, 2019 USD ($) shares	Jun. 20, 2019 shares	Dec. 31, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding (in shares)				258,101	279,766		214,630
Granted (in shares)				123,185	199,810
Stock based compensation expense \| $				$ 2.2	$ 2.5
Total unrecognized compensation expense \| $				$ 1.8
Recognition period				3 years
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Granted (in shares)		94,133
Chief Financial Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		10,000
Vice President of Technical Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		10,000
Executive Officer \| Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				1 year
Granted (in shares)				4,432
Number of independent directors \| independent_director				4
2009 Restricted Stock/Units Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (in shares)			500,000
Number of shares authorized (in shares)			800,000
Shares outstanding (in shares)				34,899
Award vesting period				1 year
Issuance under the equity incentive plan (in shares)				200,141
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)						500,000
Shares outstanding (in shares)				223,202
Award vesting period				3 years