Investments Career Builder (Details) - CareerBuilder, LLC - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Equity Method Investments [Line Items]
Revenues, net	$ 180,748	$ 176,034	$ 351,906	$ 351,188
Operating income	29,598	33,614	48,927	63,940
Net income	$ 28,842	$ 33,063	$ 49,154	$ 61,414