|12 Months Ended|
Dec. 31, 2017
|Goodwill And Intangible Assets Disclosure [Abstract]|
|Summary of Changes to Carrying Amount of Goodwill||
The following is a summary of the changes to the carrying amount of goodwill as of December 31, 2017 and December 31, 2016:
Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.
Reference 1: http://www.xbrl.org/2003/role/presentationRef