Consolidated Balance Sheets (Parenthetical) $ in Millions	Dec. 31, 2017 € / shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 € / shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 € / shares	Dec. 31, 2015 USD ($) $ / shares shares
Statement of Financial Position [Abstract]
Allowance for doubtful accounts | $		$ 6.2		$ 6.3		$ 4.5
Shareholders’ equity
Preferred shares, par value (usd per share) | $ / shares		$ 0.0001		$ 0.0001		$ 0.0001
Preferred shares, shares authorized (in shares)		10,000,000		10,000,000		10,000,000
Ordinary shares, par value (EUR per share) | € / shares	€ 0.001		€ 0.001		€ 0.001
Ordinary shares, shares authorized (in shares)		10,000,000,000		10,000,000,000		10,000,000,000