Redeemable Non-controlling Interests - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2013	Dec. 15, 2016
Redeemable Noncontrolling Interest [Line Items]
Proceeds related to trivago IPO, net of fees and expenses	$ 209,903
trivago
Redeemable Noncontrolling Interest [Line Items]
Percentage of remaining minority ownership interest that may be acquired		50.00%
Percentage of remaining minority ownership interest to be acquired		100.00%
trivago
Redeemable Noncontrolling Interest [Line Items]
Ownership interest percentage	59.70%		63.50%
Voting interest percentage	64.70%