Income Taxes - Common Distributions (Details) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Distributions Paid [Abstract]
Ordinary income	$ 0.028	$ 0.000	$ 0.080
Capital gain	0.000	0.000	0.240
Return of capital	0.043	0.069	0.150
Total distributions per share	$ 0.071	$ 0.069	$ 0.470

Taxable Return of Capital Included in Common Distribution, Per Share

No definition available.

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Namespace Prefix:	ivtp_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration