Income Taxes - Earnings Before Income Taxes and Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings before income taxes:
United States	$ 697,501	$ 672,221	$ 634,515
Foreign	125,936	153,093	139,395
Total	823,437	825,314	773,910
Income tax expense:
Partnership UBT	9,196	5,251	2,986
Corporate subsidiaries:
Federal	(943)	(4,030)	18,079
State and local	975	2,888	803
Foreign	32,290	36,529	29,365
Current tax expense	41,518	40,638	51,233
Deferred tax	236	5,178	1,877
Income tax expense	$ 41,754	$ 45,816	$ 53,110