Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:
Federal	$ (1,869,000)	$ (136,000)
State	(892,000)	(866,000)	(803,000)
Total	(2,761,000)	(1,002,000)	(803,000)
Deferred:
Federal	773,000	(2,520,000)	4,737,000
State	63,000	31,000	159,000
Total	836,000	(2,489,000)	4,896,000
Total income tax (expense) benefit	(1,925,000)	(3,491,000)	4,093,000
Reconciliation of the effective income tax rate with the applicable statutory federal income tax rate
Federal tax at statutory rate (as a percent)	35.00%	35.00%	35.00%
State taxes, net of federal benefit (as a percent)	13.40%	6.90%	3.40%
Valuation allowance (as a percent)	0.10%	(0.40%)	(6.40%)
Non-deductible stock based compensation (as a percent)	1.60%	1.60%
Other (as a percent)	(1.40%)	0.20%	(1.00%)
Effective income tax rate (as a percent)	48.70%	43.30%	31.00%
Deferred income tax assets:
Accruals not currently deductible for income taxes	1,846,000	2,429,000
Net operating loss carry-forwards	11,070,000	13,947,000
Total deferred income tax assets	12,916,000	16,376,000
Deferred income tax liabilities:
Depreciation	(19,070,000)	(20,739,000)
Total	(19,070,000)	(20,739,000)
Valuation allowance	(10,360,000)	(12,165,000)
Net deferred income tax liability	(16,514,000)	(16,528,000)
Amounts recognized in the consolidated balance sheets:
Current deferred income tax assets	76,000	78,000
Noncurrent deferred income tax assets	336,000	490,000
Noncurrent deferred income tax liabilities	(16,926,000)	(17,096,000)
Net deferred income tax liability	$ (16,514,000)	$ (16,528,000)