11. Income Taxes:

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


	December 31,
	2012		2011		2010
Federal:
Current	$	111,940	$	113,290	$	73,756
Deferred		19,814		7,486		22,814

		131,754		120,776		96,570

State:
Current		13,980		13,895		10,330
Deferred		1,530		577		1,561

		15,510		14,472		11,891

Total	$	147,264	$	135,248	$	108,461

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 37.94%, 38.29% and 34.86% for the years ended December 31, 2012, 2011 and 2010, respectively. The Company’s effective income tax rate for the year ended December 31, 2010 included a $10.9 million reduction in its income tax provision resulting from a resolution of certain matters that were under review with taxing authorities.

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


	December 31,
	2012			2011			2010
Tax at statutory rate		35.00	%		35.00	%		35.00	%
State income tax, net of federal benefit		2.60			2.66			2.42
Non-deductible expenses		0.36			0.32			0.35
Change in accrual estimates relating to uncertain tax positions		(0.15	)		0.44			(2.81	)
Other, net		0.13			(0.13	)		(0.10	)

Income tax provision		37.94	%		38.29	%		34.86	%

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


	December 31, 2012									December 31, 2011
	Total			Current			Non- Current			Total			Current			Non- Current
Allowance for uncollectible accounts	$	44,232		$	44,232		$	—		$	47,459		$	47,459		$	—
Reserves and accruals		43,345			39,942			3,403			40,807			36,828			3,979
Stock-based compensation		18,444			11,856			6,588			18,657			10,586			8,071
Net operating loss carryforward		5,624			5,624			—			3,533			3,533			—
Property and equipment		802			—			802			—			—			—
Other		509			509			—			483			483			—

Total deferred tax assets		112,956			102,163			10,793			110,939			98,889			12,050

Amortization		(136,670	)		—			(136,670	)		(105,753	)		—			(105,753	)
Accrual to cash adjustment		(33,129	)		(33,129	)		—			(28,575	)		(28,575	)		—
Property and equipment		—			—			—			(128	)		—			(128	)

Total deferred tax liabilities		(169,799	)		(33,129	)		(136,670	)		(134,456	)		(28,575	)		(105,881	)

Net deferred tax (liability) asset	$	(56,843	)	$	69,034		$	(125,877	)	$	(23,517	)	$	70,314		$	(93,831	)

The income tax benefit related to the exercise of stock options, the purchase of shares under the Company’s non-qualified employee stock purchase plan and the vesting of restricted stock 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 $6.2 million, $7.1 million, and $3.0 million for the years ended December 31, 2012, 2011 and 2010, respectively.

The Company has net operating loss carryforwards for federal and state tax purposes totaling approximately $14.9 million, $9.4 million, and $20.7 million at December 31, 2012, 2011 and 2010, respectively, expiring at various times commencing in 2014. The changes in net operating loss carryforwards in 2012 and 2011 are primarily due to timing differences related to the recognition of income for tax purposes associated with physician practice acquisitions.

As of December 31, 2012, 2011 and 2010, the Company’s liability for uncertain tax positions, excluding accrued interest and penalties, was $13.1 million, $16.2 million and $22.3 million, respectively. The Company had approximately $12.7 million of uncertain tax positions that, if recognized, would favorably impact its effective tax rate at December 31, 2012.

The following table summarizes the activity related to the Company’s liability for uncertain tax positions for the years ended December 31, 2012, 2011 and 2010 (in thousands):


	Years Ended December 31,
	2012			2011			2010
Balance at beginning of year	$	16,165		$	22,290		$	49,416
Increases related to prior year tax positions		102			44			948
Decreases related to prior year tax positions		—			—			(9,569	)
Increases related to current year tax positions		2,478			2,541			2,334
Decreases related to current year tax positions		(3,671	)		(7,203	)		(19,035	)
Settlements		—			13			(500	)
Decreases related to lapse of statutes of limitations		(2,002	)		(1,520	)		(1,304	)

Balance at end of year	$	13,072		$	16,165		$	22,290

During the years ended December 31, 2012 and 2011, the Company decreased its liability for uncertain tax positions by a total of $3.1 million and $6.1 million, respectively, which is 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 $0.3 million, $0.4 million and $1.7 million, respectively, of interest and penalties related to income tax liabilities during the years ended December 31, 2012, 2011 and 2010. At December 31, 2012 and 2011, the Company’s accrued liability for interest and penalties related to income tax liabilities totaled $9.0 million and $8.7 million, respectively.

At December 31, 2012, the Company’s total liability for uncertain tax positions of $22.1 million is included in other liabilities as presented in the Company’s Consolidated Balance Sheet. At December 31, 2011, accounts payable and accrued expenses and other liabilities as presented in the Company’s Consolidated Balance Sheet include $3.2 million and $21.7 million, respectively, related to the Company’s total liability for uncertain tax positions of $24.9 million.

The Company anticipates that its liability for uncertain tax positions will be increased over the next 12 months by additional taxes of approximately $1.1 million.

The Company is currently subject to U.S. Federal and various state income tax examinations for the tax years 2004 through 2011.