Summary of Significant Accounting Policies (Additional Information 1) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs	$ 3,856	$ 3,640	$ 3,285
Written off unamortized debt cost	600
Amortization of deferred leasing costs totaled	$ 21,300	18,500	15,200
Practical Expedient, remaining term	true
Amount of the straight-line rent receivable on the balance sheets included in rents and other receivables, net	$ 29,700	23,400
Deferred income	33,241	25,305	22,000
Amortization of deferred revenue	12,500	10,700	9,400
Equity based compensation associated with the acceleration of equity awards	3,100
Unsecured Revolving Credit Facility
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs	3,900	3,600	3,300
Written off unamortized debt cost		5,200	200
Term Loan Maturing 2022 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount		300,000
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount		400,000
Restructuring Charges [Member]
Summary Of Significant Accounting Policies [Line Items]
Company recorded equity-based compensation expense net of repurchased awards and forfeits	$ 15,000	$ 13,900	$ 10,600