Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 112,061	$ 113,401
Accounts receivable, net	45,021	43,753
Inventory	32,044	33,019
Other current assets	6,372	5,242
Total current assets	195,498	195,415
Property, plant and equipment, net	112,211	107,888
Intangibles, net	8,686	9,133
Goodwill	15,714	15,714
Deferred tax assets, net	79,755	81,449
Other long-term assets	32,044	30,232
Total assets	443,908	439,831
Current liabilities
Current portion of long-term debt and other borrowings	2,854	2,750
Revolving line of credit	0	0
Accounts payable	15,323	17,955
Accrued expenses and other liabilities	24,591	32,050
Total current liabilities	42,768	52,755
Asset retirement obligations	11,895	11,572
Long-term debt, net and other borrowings	263,293	263,709
Other long-term liabilities	42,739	40,793
Total liabilities	360,695	368,829
Commitments and contingencies (See Note 14)
Stockholders’ equity
Preferred stock ($0.01 par value, 25,000 shares authorized; no shares issued and outstanding)	0	0
Common stock ($0.01 par value, 250,000 shares authorized; 38,818 and 38,466 shares issued and outstanding, respectively)	388	385
Additional paid-in capital	242,068	239,865
Accumulated deficit	(158,191)	(168,140)
Accumulated other comprehensive loss	(1,052)	(1,108)
Total stockholders’ equity	83,213	71,002
Total liabilities and stockholders’ equity	$ 443,908	$ 439,831