Investment in Unconsolidated and Consolidated Joint Ventures - Condensed Statements of Operations and Balance Sheet Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Statement of Operations
Equity in earnings (loss)	$ 1,455	$ 1,150
Balance Sheet Information
Current assets	49,562		$ 48,893
Real Estate	45,008		44,469
Long-term debt	(76,153)		(74,215)
Unconsolidated Properties [Member]
Statement of Operations
Revenues	27,046	24,932
Net income (loss)	2,452	1,913
Partner’s share of net income (loss)	997	763
Equity in earnings (loss)	1,455	1,150
Balance Sheet Information
Current assets	22,483		20,046
Real Estate	136,069		135,459
Other assets	19,390		20,275
Long-term debt	(76,617)		(77,255)
Other liabilities	(4,399)		(4,071)
Net assets	96,926		94,454
Petro Travel Plaza Holdings
Statement of Operations
Revenues	23,954	21,861
Net income (loss)	2,291	1,934
Partner’s share of net income (loss)	916	774
Equity in earnings (loss)	1,375	1,160
Balance Sheet Information
Current assets	12,782		12,013
Real Estate	53,604		52,296
Other assets	174		264
Long-term debt	(14,707)		(14,973)
Other liabilities	(2,852)		(2,890)
Net assets	49,001		46,710
Five West Parcel LLC
Statement of Operations
Revenues	790	995
Net income (loss)	328	182
Partner’s share of net income (loss)	164	91
Equity in earnings (loss)	164	91
Balance Sheet Information
Current assets	3,751		3,277
Real Estate	13,530		13,704
Other assets	324		297
Long-term debt	(10,585)		(10,725)
Other liabilities	(479)		(340)
Net assets	6,541		6,213
18-19 West LLC
Statement of Operations
Revenues	2	7
Net income (loss)	(43)	(2)
Partner’s share of net income (loss)	(21)	(1)
Equity in earnings (loss)	(22)	(1)
Balance Sheet Information
Current assets	5		23
Real Estate	4,617		4,617
Other assets	0		0
Long-term debt	0		0
Other liabilities	(5)		0
Net assets	4,617		4,640
TRCC/Rock Outlet Center
Statement of Operations
Revenues	2,300	2,069
Net income (loss)	(124)	(201)
Partner’s share of net income (loss)	(62)	(101)
Equity in earnings (loss)	(62)	(100)
Balance Sheet Information
Current assets	5,945		4,733
Real Estate	64,318		64,842
Other assets	18,892		19,714
Long-term debt	(51,325)		(51,557)
Other liabilities	(1,063)		(841)
Net assets	36,767		36,891
Rental income	2,800	2,700
Non-cash tenant allowance amortization	500	600
Centennial-VIE
Statement of Operations
Revenues	36	93
Net income (loss)	(57)	(62)
Partner’s share of net income (loss)	(14)	(16)
Equity in earnings (loss)	0	$ 0
Balance Sheet Information
Current assets	131		230
Real Estate	82,517		81,742
Other assets	4		9
Long-term debt	0		0
Other liabilities	(633)		(754)
Net assets	$ 82,019		$ 81,227