Related Party Transactions and Arrangements (Related Party Fees and Expenses) (Details) - Affiliated Entity [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Related party expenses	$ 26,529	$ 37,222	$ 54,023	$ 91,479
Tenant Improvement And Furniture Costs [Member]
Related Party Transaction [Line Items]
Related party expenses					$ 8,500
Offering Related Costs [Member]
Related Party Transaction [Line Items]
Related party expenses	0	2,000	0	2,150
Acquisition Related Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses	0	113	0	1,652
Merger And Other Non-Routine Transactions [Member]
Related Party Transaction [Line Items]
Related party expenses	0	40	0	137,778
Management Fees To Affiliates [Member]
Related Party Transaction [Line Items]
Related party expenses	0	0	0	13,888
General and Administrative Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses	0	437	0	16,029
Indirect Affiliate Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses	0	3,997	0	4,495
Total Expenses and Capitalized Costs [Member]
Related Party Transaction [Line Items]
Related party expenses	$ 0	$ 6,587	$ 0	$ 175,992