Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
Accrued expenses	$ 349	$ 318
Deferred revenues	370	697
Capitalization of costs	1,843	1,937
Pension adjustment	2,883	2,937
Stock grant expense	2,500	2,674
State deferred taxes	116	25
Book deferred gains	1,176	941
Joint venture allocations	533	1,091
Provision for additional capitalized costs	699	699
Interest rate swap	810	0
Other	39	155
Total deferred income tax assets	11,318	11,474
Deferred income tax liabilities:
Deferred gains	490	32
Depreciation	2,892	3,100
Cost of sales allocations	872	872
Joint venture allocations	5,070	4,914
Straight line rent	590	611
Prepaid expenses	333	298
State deferred taxes	208	256
Interest rate swap	0	28
Other	150	134
Total deferred income tax liabilities	10,605	10,245
Net deferred income tax asset	713	1,229
Allowance for deferred tax assets	0	0
Net deferred taxes	$ 713	$ 1,229