Investment in Unconsolidated and Consolidated Joint Ventures - Condensed Statements of Operations and Balance Sheet Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Information
Assets	$ 214,155	$ 215,203
Borrowings	(121,326)	(114,272)
Equity	87,568	96,107
Investment In	28,602	30,031
Statement of Operations
Revenues	133,549	121,612	$ 114,222
Earnings(Loss)	5,734	6,371	11,782
Equity in Earnings (Loss)	3,834	4,227	7,098
Petro Travel Plaza Holdings, LLC
Balance Sheet Information
Assets	69,096	67,435
Borrowings	(15,283)	(15,279)
Equity	51,377	49,705
Investment In	18,426	17,422
Statement of Operations
Revenues	119,083	105,507	100,605
Earnings(Loss)	9,672	10,418	12,077
Equity in Earnings (Loss)	5,803	6,251	7,246
Five West Parcel, LLC
Balance Sheet Information
Assets	15,157	15,738
Borrowings	(9,173)	(9,711)
Equity	5,751	5,972
Investment In	2,691	2,802
Statement of Operations
Revenues	2,731	2,824	2,887
Earnings(Loss)	778	905	1,029
Equity in Earnings (Loss)	389	452	515
18-19 West, LLC
Balance Sheet Information
Assets	4,654	4,704
Borrowings	0	0
Equity	4,654	4,704
Investment In	1,783	1,782
Statement of Operations
Revenues	13	11	10
Earnings(Loss)	(102)	(97)	(129)
Equity in Earnings (Loss)	(51)	(48)	(65)
TRCC/Rock Outlet Center, LLC
Balance Sheet Information
Assets	75,194	81,610
Borrowings	(46,826)	(48,769)
Equity	27,531	32,177
Investment In	5,702	8,025
Statement of Operations
Revenues	6,418	9,615	9,542
Earnings(Loss)	(4,645)	(2,347)	(367)
Equity in Earnings (Loss)	(2,323)	(1,173)	(184)
Non-cash tenant allowance amortization	1,700	1,800	1,900
TRC-MRC 1, LLC
Balance Sheet Information
Assets	29,692	25,380
Borrowings	(25,030)	(19,433)
Equity	4,018	4,541
Investment In	0	0
Statement of Operations
Revenues	1,323	0	0
Earnings(Loss)	(498)	(3)	0
Equity in Earnings (Loss)	(249)	(2)	0
TRC-MRC 2, LLC
Balance Sheet Information
Assets	20,362	20,336
Borrowings	(25,014)	(21,080)
Equity	(5,763)	(992)
Investment In	0	0
Statement of Operations
Revenues	3,981	3,655	1,178
Earnings(Loss)	529	(2,505)	(828)
Equity in Earnings (Loss)	265	(1,253)	(414)
Non-cash amortization of purchase accounting adjustments related to in-place leases	800	4,000
Centennial Founders, LLC
Balance Sheet Information
Assets	93,840	89,721
Borrowings	0	0
Equity	93,188	88,862
Statement of Operations
Revenues	297	456	520
Earnings(Loss)	$ (249)	$ (144)	$ (246)