Summary of Significant Accounting Policies - Acquisition Related Expenses and Other One-Time Transaction Related Expenses (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Merger related costs:
Strategic advisory services		$ 0	$ 3,150	$ 0	$ 35,765
Transfer taxes		0	0	0	5,109
Legal fees and expenses		0	579	0	5,126
Personnel costs and other reimbursements		0	0	0	751
Multi-tenant spin off		0	2,270	0	7,450
Other fees and expenses		0	0	0	1,676
Other non-routine transaction related costs:
Post-transaction support services		0	0	0	14,251
Subordinated distribution fee		0	0	0	78,244
Audit Committee Investigation and related matters		9,251	0	38,953	0
Furniture, fixtures and equipment		0	0	0	14,085
Legal fees and expenses		(294)	743	2,659	2,569
Personnel costs and other reimbursements		0	0	0	2,718
Other fees and expenses		0	890	632	7,608
Total	[1]	$ 8,957	$ 7,632	$ 42,244	$ 175,352

[1] Includes $137.8 million of expenses incurred during the nine months ended September 30, 2014, paid to affiliates. No such expenses were incurred during the three months ended September 30, 2014 or the three and nine months ended September 30, 2015.