Agreements and Transactions with Related Parties - Due from Affiliates (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Due from affiliates
Short-term loans to affiliates	$ 237,613	$ 0
Deferred acquisition fees receivable	21,967	33,386
Distribution and shareholder servicing fees	19,341	11,801
Current acquisition fees receivable	8,024	4,909
Accounts receivable	5,005	3,910
Reimbursable costs	4,427	5,579
Asset management fees receivable	2,449	2,172
Organization and offering costs	784	461
Due from affiliates	$ 299,610	$ 62,218