Business Segment Information (Geographic Data) (Details) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Mar. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
Sep. 30, 2015
USD ($)
|
Jun. 30, 2015
USD ($)
|
Mar. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Sep. 30, 2014
USD ($)
|
Jun. 30, 2014
USD ($)
|
Mar. 31, 2016
USD ($)
geographic_area
|
Mar. 31, 2015
USD ($)
|
Mar. 31, 2014
USD ($)
|
|
| Geographic Data | |||||||||||
| Number of geographic areas the Company operates in | geographic_area | 2 | ||||||||||
| Operating revenues | $ 49,857 | $ 55,144 | $ 61,932 | $ 56,108 | $ 60,225 | $ 60,145 | $ 61,472 | $ 63,338 | $ 223,041 | $ 245,180 | $ 287,346 |
| Assets | 421,717 | 466,025 | 421,717 | 466,025 | |||||||
| United States of America | |||||||||||
| Geographic Data | |||||||||||
| Operating revenues | 217,349 | 234,554 | 275,161 | ||||||||
| Assets | 415,422 | 458,197 | 415,422 | 458,197 | |||||||
| Europe | |||||||||||
| Geographic Data | |||||||||||
| Operating revenues | 5,692 | 10,626 | $ 12,185 | ||||||||
| Assets | $ 6,295 | $ 7,828 | $ 6,295 | $ 7,828 | |||||||