Segment Reporting (Narratives) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segment	Jun. 30, 2013
Segment Reporting Information [Line Items]
Number of business segments			2
Segment Reporting Information Profit Loss
Operating expenses	$ 161,357	$ 80,811	$ 332,963	$ 156,005
Cost of Reimbursable Expense	47,674	18,507	93,420	33,592
Reimbursable costs from affiliates	41,925	15,467	81,657	27,435
Stock-based compensation expense	7,957	8,429	15,000	17,578
Real Estate Ownership
Segment Reporting Information Profit Loss
Operating expenses	93,112	42,593	200,339	82,491
Investment Management
Segment Reporting Information Profit Loss
Operating expenses	68,245	38,218	132,624	73,514
Stock-based compensation expense	7,700	7,500	14,600	16,500
CPA: 16 - Global | Real Estate Ownership
Segment Reporting Information Profit Loss
Operating expenses			$ 30,400