Reportable Segments - Revenue and Total Assets by Geographic Area (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues and total assets by geographic area
% of Revenue	100.00%	100.00%	100.00%	100.00%
Non-United States | Maximum
Revenues and total assets by geographic area
% of Revenue			1.00%
Canada
Revenues and total assets by geographic area
% of total assets			1.00%