Derivative Financial Instruments - Additional Information (Details) - USD ($)			12 Months Ended
	Jul. 15, 2016	Jul. 14, 2016	Dec. 31, 2017	Feb. 09, 2018	Jul. 13, 2016
Derivative [Line Items]
Current Fiscal Year End Date			--12-31
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			$ 6,900,000
Loss on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring		$ 40,600,000
Equity Offering [Member]
Derivative [Line Items]
Proceeds from Issuance of Common Stock	$ 400,100,000
Unsecured Debt [Member]
Derivative [Line Items]
Unsecured Debt Repayment					$ 300,000,000
Swap [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			8,400,000
Assets [Member]
Derivative [Line Items]
Derivative, Notional Amount			$ 220,000,000
Subsequent Event [Member] | Derivative @ 2.899% 285M 10Yr Treasury Rate Lock [Member]
Derivative [Line Items]
Derivative, Notional Amount				$ 285,000,000
Derivative, Fixed Interest Rate				2.899%