Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 56,885	$ 113,401
Accounts receivable, net	45,527	43,753
Inventory	32,414	33,019
Other current assets	5,035	5,242
Total current assets	139,861	195,415
Property, plant and equipment, net	113,117	107,888
Intangibles, net	8,239	9,133
Goodwill	15,714	15,714
Deferred tax assets, net	79,170	81,449
Other long-term assets	34,149	30,232
Total assets	390,250	439,831
Current liabilities
Current portion of long-term debt and other borrowings	10,136	2,750
Accounts payable	17,149	17,955
Accrued expenses and other liabilities	26,072	32,050
Total current liabilities	53,357	52,755
Asset retirement obligations	12,237	11,572
Long-term debt, net and other borrowings	188,706	263,709
Other long-term liabilities	43,703	40,793
Total liabilities	298,003	368,829
Commitments and contingencies
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; 39,043 and 38,466 shares issued and outstanding, respectively)	390	385
Additional paid-in capital	244,600	239,865
Accumulated deficit	(151,779)	(168,140)
Accumulated other comprehensive loss	(964)	(1,108)
Total stockholders’ equity	92,247	71,002
Total liabilities and stockholders’ equity	$ 390,250	$ 439,831