Annual report pursuant to Section 13 and 15(d)

Segment Reporting (Narrative) (Details)

v3.20.4
Segment Reporting (Narrative) (Details)
3 Months Ended 12 Months Ended
Dec. 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2020
USD ($)
segment
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Segment Reporting Information [Line Items]                      
Number of business segments | segment                 2    
Total revenues $ 76,564,000 $ 79,197,000 $ 74,197,000 $ 83,604,000 $ 88,227,000 $ 89,038,000 $ 88,138,000 $ 91,799,000 $ 313,562,000 $ 357,202,000 $ 371,724,000
Foreign Locations [Member]                      
Segment Reporting Information [Line Items]                      
Total revenues                 0 0 $ 0
Long lived assets $ 0       $ 0       $ 0 $ 0