11. Income Taxes:

The components of the income tax provision are as follows (in thousands):


	December 31,
	2013		2012		2011
Federal:
Current	$	134,938	$	111,940	$	113,290
Deferred		14,784		19,814		7,486

		149,722		131,754		120,776

State:
Current		17,037		13,980		13,895
Deferred		1,136		1,530		577

		18,173		15,510		14,472

Total	$	167,895	$	147,264	$	135,248

The Company files its tax return on a consolidated basis with its subsidiaries. The remaining affiliated professional contractors file tax returns on an individual basis.

The effective tax rate was 37.44%, 37.94% and 38.29% for the years ended December 31, 2013, 2012 and 2011, respectively.

The differences between the effective rate and the United States federal income tax statutory rate are as follows:


	December 31,
	2013			2012			2011
Tax at statutory rate		35.00	%		35.00	%		35.00	%
State income tax, net of federal benefit		2.63			2.60			2.66
Non-deductible expenses		0.27			0.36			0.32
Change in accrual estimates relating to uncertain tax positions		(0.48	)		(0.15	)		0.44
Other, net		0.02			0.13			(0.13	)

Income tax provision		37.44	%		37.94	%		38.29	%

The significant components of deferred income tax assets and liabilities are as follows (in thousands):


	December 31, 2013									December 31, 2012
	Total			Current			Non- Current			Total			Current			Non- Current
Allowance for uncollectible accounts	$	42,425		$	42,425		$	—		$	44,232		$	44,232		$	—
Reserves and accruals		52,519			49,128			3,391			43,345			39,942			3,403
Stock-based compensation		16,457			10,914			5,543			18,444			11,856			6,588
Net operating loss carryforward		6,385			6,385			—			5,624			5,624			—
Property and equipment		1,310			—			1,310			802			—			802
Other		446			446			—			509			509			—

Total deferred tax assets		119,542			109,298			10,244			112,956			102,163			10,793

Amortization		(162,399	)		—			(162,399	)		(136,670	)		—			(136,670	)
Accrual to cash adjustment		(37,818	)		(37,818	)		—			(33,129	)		(33,129	)		—

Total deferred tax liabilities		(200,217	)		(37,818	)		(162,399	)		(169,799	)		(33,129	)		(136,670	)

Net deferred tax (liability) asset	$	(80,675	)	$	71,480		$	(152,155	)	$	(56,843	)	$	69,034		$	(125,877	)

The income tax benefit related to the exercise of stock options, the vesting of restricted and deferred stock and the purchase of shares under the Company’s non-qualified employee stock purchase plan in excess of amounts recorded as equity compensation expense reduces taxes currently payable and is credited to additional paid-in capital. Such amounts totaled approximately $19.0 million, $6.2 million, and $7.1 million for the years ended December 31, 2013, 2012 and 2011, respectively.

The Company has net operating loss carryforwards for federal and state tax purposes totaling approximately $16.9 million, $14.9 million, and $9.4 million at December 31, 2013, 2012 and 2011, respectively, expiring at various times commencing in 2019. The changes in net operating loss carryforwards in 2013 and 2012 are primarily due to timing differences related to the recognition of income for tax purposes associated with physician practice acquisitions.

As of December 31, 2013, 2012 and 2011, the Company’s liability for uncertain tax positions, excluding accrued interest and penalties, was $14.9 million, $13.1 million and $16.2 million, respectively. The Company had approximately $14.5 million of uncertain tax positions that, if recognized, would favorably impact its effective tax rate at December 31, 2013.

The following table summarizes the activity related to the Company’s liability for uncertain tax positions for the years ended December 31, 2013, 2012 and 2011 (in thousands):


	Years Ended December 31,
	2013			2012			2011
Balance at beginning of year	$	13,072		$	16,165		$	22,290
Increases related to prior year tax positions		338			102			44
Decreases related to prior year tax positions		(38	)		—			—
Increases related to current year tax positions		2,955			2,478			2,541
Decreases related to current year tax positions		—			(3,671	)		(7,203	)
Settlements		—			—			13
Decreases related to lapse of statutes of limitations		(1,425	)		(2,002	)		(1,520	)

Balance at end of year	$	14,902		$	13,072		$	16,165

During the year ended December 31, 2013, the Company increased its liability for uncertain tax positions by a total of $1.8 million, primarily related to additional taxes on current year positions, partially offset by decreases due to the expiration of statutes of limitation. During the year ended December 31, 2012, the Company decreased its liability for uncertain tax positions by a total of $3.1 million, which was primarily related to reclassifications of certain temporary differences to deferred taxes payable.

The Company includes interest and penalties related to income tax liabilities in income tax expense. The Company recognized a decrease of $0.6 million related to interest and penalties during the year ended December 31, 2013. The Company recognized $0.3 million and $0.4 million, respectively, of interest and penalties related to income tax liabilities during the years ended December 31, 2012 and 2011. At December 31, 2013 and 2012, the Company’s accrued liability for interest and penalties related to income tax liabilities totaled $8.4 million and $9.0 million, respectively.

At December 31, 2013 and 2012, the Company’s total liability for uncertain tax positions of $23.3 million and $22.1 million, respectively, is included in other liabilities as presented in the Company’s Consolidated Balance Sheet.

The Company anticipates that its liability for uncertain tax positions will be increased by approximately $3.8 million for additional taxes and decreased by approximately $1.5 million related to the expiration of certain statutes of limitation over the next 12 months.

The Company is currently subject to U.S. Federal and various state income tax examinations for the tax years 2004 through 2012.