XML 57 R43.htm IDEA: XBRL DOCUMENT v3.8.0.1
Revenue Recognition - Narrative (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Revenue from Contract with Customer [Abstract]    
Contract receivable $ 112,500 $ 112,300
Deferred revenue $ 10,021 $ 9,522