Income taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income taxes [Abstract]

Summary of provision for income taxes

	2013			2012
Federal – current	$	799,264		$	1,011,543
Federal – deferred		(333	)		9,842
State – current		17,835			33,398
State – deferred		(954	)		295
Total provision for income taxes	$	815,812		$	1,055,078

Summary of reconciliation of the provision for income taxes at the statutory rate to the reported provision for income taxes

	2013			%			2012			%
Income Tax computed at statutory rate	$	765,367			34.0	%	$	1,016,323			34.0	%
State tax, net of federal benefit		12,344			0.5	%		21,637			0.7	%
Loss attributable to noncontrolling interest		8,746			0.4	%		9,581			0.3	%
Share based compensation		85,109			3.7	%		66,600			2.2	%
Other, permanent adjustments		(59,247	)		-2.6	%		(86,666	)		-2.9	%
Tax credits and prior year tax adj.		3.493			0.2	%		27,603			1.0	%
Provision for income taxes	$	815,812			36.2	%	$	1,055,078			35.3	%

Summary of deferred tax asset and liability

	2013				2012
Deferred taxes – current
Reserves for bad debts, inventories, and other accruals		$	137,821			$	120,740
Depreciation of property and equipment			(73,156)				(64,519	)
Total deferred tax asset current		$	64,665			$	56,221
Deferred taxes - non-current
Depreciation of property and equipment		$	(237,635	)		$	(230,478	)
Total deferred tax liability non-current		$	(237,635	)		$	(230,478	)