Basis of Presentation and Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of year	$ 3,487	$ 3,998	$ 4,325
Provision for credit losses and accrued straight-line rent, net of recoveries	3,461	2,786	2,771
Accounts written off	(2,648)	(3,297)	(3,098)
Balance, end of year	$ 4,300	$ 3,487	$ 3,998