Investments Career Builder (Details) - CareerBuilder, LLC - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of Equity Method Investments [Line Items]
Revenues, net	$ 180,917	$ 175,540	$ 532,823	$ 526,728
Operating income	28,506	37,353	77,433	101,293
Net income	$ 28,446	$ 36,470	$ 77,600	$ 97,884