XML 50 R12.htm IDEA: XBRL DOCUMENT v3.20.1
Other Long-Term Liabilities
 3 Months Ended
Mar. 31, 2020
Other Liabilities Disclosure [Abstract]  
Other Long-Term Liabilities Other Long-Term Liabilities

Other long-term liabilities are summarized as follows (in thousands):

 
March 31, 2020
 
December 31, 2019
Black lung obligations
$
29,871

 
$
30,233

Other
1,679

 
1,197

Total other long-term liabilities
$
31,550

 
$
31,430