Quarterly report pursuant to Section 13 or 15(d)

Segment Reporting (Narrative) (Details)

v3.10.0.1
Segment Reporting (Narrative) (Details)
3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Jun. 30, 2018
USD ($)
segment
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Segment Reporting Information [Line Items]          
Number of business segments | segment     2    
Total revenues $ 126,589,000 $ 162,766,000 $ 265,556,000 $ 312,653,000  
Foreign Locations [Member]          
Segment Reporting Information [Line Items]          
Total revenues     0 $ 0  
Long lived assets $ 0   $ 0   $ 0