Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets
Unearned and deferred compensation	$ 33,100	$ 35,525
Net operating loss and other tax credit carryforwards	31,381	19,553
Basis differences — foreign investments	28,324	6,975
Other	5,560	3,788
Total deferred tax assets	98,365	65,841
Valuation allowance	(27,350)	(29,746)
Net deferred tax assets	71,015	36,095
Deferred Tax Liabilities
Basis differences — foreign investments	(123,269)	(81,058)
Basis differences — equity investees	(17,282)	(19,925)
Deferred revenue	(7,318)	(8,654)
Total deferred tax liabilities	(147,869)	(109,637)
Net Deferred Tax Liability	$ (76,854)	$ (73,542)