XML 25 R65.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Common and Subordinated Units (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2019
Nov. 05, 2018
Class of Stock [Line Items]      
Partners' capital account, distribution amount per share (in dollars per share) $ 1.35 $ 1.35  
Authorized repurchase amount     $ 75,000,000.0
Series B Cumulative Convertible Preferred Units      
Class of Stock [Line Items]      
Preferred units minimum voting rights rate (percent) 15.00% 15.00%  
Preferred units distribution rate (percent)   7.00%  
Common Units      
Class of Stock [Line Items]      
Common units repurchased, units   136,665  
Aggregate cost of units repurchased   $ 2,200,000  
Common units repurchased, units   136,665  
Aggregate cost of units repurchased   $ 2,200,000  
Common Units | BSMNovember Two Thousand Twenty Eighteen Repurchase Program      
Class of Stock [Line Items]      
Aggregate cost of units repurchased $ 4,200,000    
Aggregate cost of units repurchased $ 4,200,000