Unconsolidated Real Estate Affiliates (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 37,109				$ 39,700				$ 37,109	$ 39,700	$ 45,782
Investments in unconsolidated real estate affiliates	92,414				93,670				92,414	93,670
SUMMARIZED COMBINED BALANCE SHEETS-UNCONSOLIDATED REAL ESTATE AFFILIATES
Real Estate Investment Property, Net	2,030,419				2,013,590				2,030,419	2,013,590
Acquired intangible assets, net	84,468				103,226				84,468	103,226
TOTAL ASSETS	2,196,594				2,197,107				2,196,594	2,197,107
Notes Payable	818,095				879,022				818,095	879,022
Acquired intangible liabilities, net	16,024				19,649				16,024	19,649
TOTAL LIABILITIES	1,009,302				1,018,850				1,009,302	1,018,850
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,187,292				1,178,257				1,187,292	1,178,257	1,234,541	$ 745,490
Liabilities and Equity	2,196,594				2,197,107				2,196,594	2,197,107
Investment Building and Building Improvements	1,441,765				1,465,448				1,441,765	1,465,448
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	163,314				132,639				163,314	132,639
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues	43,055	$ 43,319	$ 42,227	$ 42,082	42,536	$ 42,293	$ 40,427	$ 39,696	170,683	164,952	131,859
Operating Costs and Expenses									143,613	139,079	115,720
Operating Income (Loss)											115,720
Interest Expense									33,135	28,094	22,612
Net income (loss)									25,604	22,894	5,540
Net income (loss) attributable to Jones Lang LaSalle Income Property Trust, Inc.	(6,882)	$ (3,301)	$ 3,106	$ 32,644	8,822	$ 10,670	$ 3,798	$ (742)	25,567	22,548	4,935
Unconsolidated Real Estate Affiliates [Member]
SUMMARIZED COMBINED BALANCE SHEETS-UNCONSOLIDATED REAL ESTATE AFFILIATES
Real Estate Investment Property, Net	227,451				113,095				227,451	113,095
Acquired intangible assets, net	19,016				22,822				19,016	22,822
Other Assets	6,315				4,061				6,315	4,061
TOTAL ASSETS	252,782				139,978				252,782	139,978
Notes Payable	71,003				0				71,003	0
Acquired intangible liabilities, net	4,174				5,310				4,174	5,310
Other Liabilities	2,771				2,029				2,771	2,029
TOTAL LIABILITIES	77,948				7,339				77,948	7,339
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	174,834				132,639				174,834	132,639
Liabilities and Equity	252,782				139,978				252,782	139,978
Proceeds from Other Equity									(11,630)	0
Investment Building and Building Improvements	110				0				110	0
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues									16,188	11,952	6,589
Operating Costs and Expenses									16,522	10,795	5,983
Net income (loss)									1,644	(1,157)	(606)
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable									593	0	0
Net income (loss) attributable to Jones Lang LaSalle Income Property Trust, Inc.									1,051	(1,157)	(606)
NYC Retail Portfolio [Member]
Real Estate Properties [Line Items]
Investments, Fair Value Disclosure	335,704				337,060				335,704	337,060
Cash and Cash Equivalents, at Carrying Value	2,560				8,423				2,560	8,423
SUMMARIZED COMBINED BALANCE SHEETS-UNCONSOLIDATED REAL ESTATE AFFILIATES
Other Assets	3				149				3	149
TOTAL ASSETS	338,267				345,632				338,267	345,632
TOTAL LIABILITIES	567				355				567	355
Partners' Capital	337,700				345,277				337,700	345,277
Liabilities and Equity	$ 338,267				$ 345,632				338,267	345,632
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues									3,333	14,386	6,864
Net Investment Income									1,330	11,740	5,289
Unrealized Gain (Loss) on Investments									6,675	24,686	30,994
Net income (loss)									8,005	36,426	36,283
Unconsolidated Real Estate Affiliates [Member]
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Operating Income (Loss)									(334)	1,157	606
Interest Expense									$ (1,310)	$ 0	$ 0