Income Taxes (Details 3)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of effective tax rate of the Company with U.S. federal statutory income tax rate
United States federal statutory income tax rate	21.00%	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit (as a percent)		2.20%	1.20%	1.30%
Percentage depletion deduction (as a percent)		12.90%	(25.00%)	5.70%
Change in valuation allowance (as a percent)		48.50%	(32.40%)	(86.90%)
AMT credit monitization		85.60%	0.00%	0.00%
Other non-deductible expenses		(2.10%)	1.70%	(0.50%)
Stock compensation		(5.80%)	12.10%	(1.50%)
Non-deductible goodwill impairment		0.00%	0.00%	(9.10%)
Current and deferred tax adjustments		(9.00%)	(4.70%)	(4.70%)
Impact of federal corporate tax change		(87.30%)	0.00%	0.00%
Other		0.00%	0.40%	0.60%
Effective tax rate (as a percent)		80.00%	(11.70%)	(60.10%)