Income Taxes and Distributions (Details 2) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Income Tax Expense
Tax at statutory rate on earnings from continuing operations before unconsolidated entities, noncontrolling interests and income taxes		$ 199,588	$ 372,030	$ 313,250
Change in valuation allowance	[1]	30,445	(2,128)	13,759
Tax at statutory rate on earnings not subject to federal income taxes		(234,468)	(399,571)	(319,832)
Foreign Permanent Depreciation		10,065	9,205	7,500
Other differences		14,498	1,336	(8,226)
Income tax (expense) benefit		$ 20,128	$ (19,128)	$ 6,451

[1] Excluding purchase price accounting.