Software, net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Minimum
Business Acquisition [Line Items]
Estimated economic life	2 years
Maximum
Business Acquisition [Line Items]
Estimated economic life	16 years
Internal use software
Business Acquisition [Line Items]
Capitalized computer software, additions	$ 74.4	$ 70.9
Internal use software | Minimum
Business Acquisition [Line Items]
Estimated economic life	2 years
Internal use software | Maximum
Business Acquisition [Line Items]
Estimated economic life	10 years
External use software | Minimum
Business Acquisition [Line Items]
Estimated economic life	8 years
External use software | Maximum
Business Acquisition [Line Items]
Estimated economic life	10 years
Regulatory approval costs | Minimum
Business Acquisition [Line Items]
Estimated economic life	2 years
Regulatory approval costs | Maximum
Business Acquisition [Line Items]
Estimated economic life	4 years