Related Party Transactions and Arrangements - Related Party Expenses and Fees (Details) - Affiliated Entity [Member] - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Offering Related Costs [Member]
Related Party Transaction [Line Items]
Related party expenses			$ 2,150,000
Acquisition Related Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses			1,652,000
Litigation, Merger and Other Non-Routine Transactions, Net of Insurance Recoveries [Member]
Related Party Transaction [Line Items]
Related party expenses			137,778,000
Management Fees To Affiliates [Member]
Related Party Transaction [Line Items]
Related party expenses			13,888,000
General and Administrative Expense [Member]
Related Party Transaction [Line Items]
Related party expenses	$ 0	$ 0	16,089,000
Indirect Affiliate Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses			10,975,000
Total Expenses and Capitalized Costs [Member]
Related Party Transaction [Line Items]
Related party expenses	$ 0	$ 0	$ 182,532,000