Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 3,131,000	$ 2,638,000	$ 4,353,000
State	580,000	336,000	824,000
Current income taxes	3,711,000	2,974,000	5,177,000
Deferred:
Federal	508,000	1,262,000	641,000
State	(71,000)	(30,000)	99,000
Deferred income taxes	437,000	1,232,000	740,000
Total income tax provision	4,148,000	4,206,000	$ 5,917,000
Operating Loss Carryforwards	415,000
Future benefit of the federal net operating loss carryforwards, limit per year	300,000
Deferred tax assets:
Reserves	532,000	428,000
Inventory capitalization	407,000	264,000
Compensation programs	501,000	404,000
Retirement liability	27,000	35,000
Equity-based compensation	290,000	276,000
Net operating loss carryforwards	141,000	242,000
Deferred rent	10,000	36,000
Intangible assets	264,000	188,000
Total deferred tax asset	2,172,000	1,873,000
Deferred tax liabilities:
Excess of book over tax basis of fixed assets	(4,186,000)	(3,471,000)
Goodwill	(869,000)	(848,000)
Total deferred tax liabilities	5,055,000	4,319,000
Net long-term deferred tax liabilities	(2,883,000)	$ (2,446,000)
Long-term deferred tax assets / (liabilities):
Deferred tax assets	$ 2,200,000
Reconciliation of actual tax provision from expected tax provision
Computed "expected" tax rate (as a percent)	34.00%	34.00%	34.00%
Increase (decrease) in income taxes resulting from:
State taxes, net of federal tax benefit (as a percent)	2.30%	1.10%	3.60%
Meals and entertainment (as a percent)	0.30%	0.30%	0.10%
R&D credits (as a percent)	(0.80%)	(0.70%)	(1.00%)
Domestic production deduction (as a percent)	(2.50%)	(1.40%)	(2.40%)
Non-deductible ISO stock option expense (as a percent)	0.40%	0.40%	0.20%
Unrecognized tax benefits (as a percent)		1.30%	(0.10%)
Other (as a percent)	1.60%	0.80%
Effective tax rate (as a percent)	35.30%	35.80%	34.40%
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits (UTB) resulting from uncertain tax positions
Gross UTB balance at beginning of fiscal year	$ 230,000	$ 275,000
Reductions for tax positions of prior years	(68,000)	(45,000)
Gross UTB balance at the end of fiscal year	162,000	230,000	$ 275,000
Total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate	162,000	230,000
Accrued interest and penalties	$ 153,000	$ 195,000