Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred income tax assets:
Accrued expenses	$ 525	$ 222
Deferred revenues	512	829
Capitalization of costs	1,758	1,746
Pension adjustment	4,262	3,660
Stock grant expense	7,005	6,955
State deferred taxes	777	761
Book deferred gains	963	963
Provision for additional capitalized costs	1,003	1,210
Other	73	382
Total deferred income tax assets	16,878	16,728
Deferred income tax liabilities:
Deferred gains	1,390	1,390
Depreciation	3,374	2,504
Cost of sales allocations	1,252	1,252
Joint venture allocations	2,084	1,054
Straight line rent	1,063	1,117
Prepaid expenses	212	189
State deferred taxes	345	574
Other	785	704
Total deferred income tax liabilities	10,505	8,784
Net deferred income tax asset	6,373	7,944
Allowance for deferred tax assets	0	0
Net deferred taxes	$ 6,373	$ 7,944