Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax assets:
Accrued expenses	$ 578	$ 608
Deferred revenues	652	498
Capitalization of costs	3,023	2,746
Pension adjustment	4,396	4,502
Stock grant expense	3,593	2,936
State deferred taxes	221	200
Book deferred gains	1,711	1,711
Joint venture allocations	860	587
Provision for additional capitalized costs	1,003	1,003
Interest rate swap	1,244	954
Other	3	3
Total deferred income tax assets	17,284	15,748
Deferred income tax liabilities:
Deferred gains	1,390	1,390
Depreciation	5,040	4,228
Cost of sales allocations	1,252	1,252
Joint venture allocations	3,121	2,456
Straight line rent	929	947
Prepaid expenses	149	191
State deferred taxes	617	501
Other	127	207
Total deferred income tax liabilities	12,625	11,172
Net deferred income tax asset	4,659	4,576
Allowance for deferred tax assets	0	0
Net deferred taxes	$ 4,659	$ 4,576