CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Intangible lease assets, accumulated amortization	$ 87,391	$ 99,145
Tenant receivables, allowance for doubtful accounts	504	539
Deferred lease costs, accumulated amortization	183,611	180,120
Liabilities:
Intangible lease liabilities, accumulated amortization	$ 59,144	$ 55,847
Stockholders' Equity:
Shares-in-trust, shares authorized	150,000,000	150,000,000
Shares-in-trust, shares outstanding	0	0
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	126,218,554	142,358,940
Common stock, shares outstanding	126,218,554	142,358,940
Unsecured Debt
Liabilities:
Discount (premium) and unamortized debt issuance costs	$ 9,879	$ 7,689
Secured Debt
Liabilities:
Discount (premium) and unamortized debt issuance costs	(645)	(946)
Building and building improvements
Assets:
Buildings and improvements, accumulated depreciation	$ 772,093	$ 683,770