Summary of Significant Accounting Policies Receivables, Trade and Other Accounts Receivalbe, Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Document Fiscal Year Focus	2017
Provision for Doubtful Accounts	$ (8,040)	$ (5,460)
Straight Line Rent	93,284	73,384
Tenant Reimbursements	14,825	9,221
Billed Tenant Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	25,329	15,599
Other Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	34,472	12,058
Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	15,803	10,481
straight line rent [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Doubtful Accounts	(4,688)	(3,561)
Parent Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	170,985	111,722
Straight Line Rent	19,004	7,219	$ 8,231
Tenant Reimbursements	$ 223,455	$ 140,611	$ 125,295