13. Income Taxes

The income tax provision for the years ended December 31, 2014, 2015 and 2016 is summarized below (in thousands):


	2014		2015		2016
Current:
Federal	$	25,285	$	25,515	$	26,015
State		4,490		4,538		4,869
Total current		29,775		30,053		30,884
Deferred:
Federal		141		(3,634)		(7,748)
State		344		(311)		(646)
Total deferred		485		(3,945)		(8,394)
Total provision for income taxes	$	30,260	$	26,108	$	22,490

The tax effects of the principal temporary differences that give rise to the Company’s deferred tax assets are as follows as of December 31, 2015 and 2016 (in thousands):


	2015		2016
Stock-based compensation	$	16,742	$	20,477
Property and equipment		(9,417)		(6,059)
Other facility-related costs		8,535		5,242
Deferred revenue		4,267		7,182
Tuition receivable		3,908		3,922
Deferred leasing costs		3,362		3,064
Prepaid compensation		—		(1,139)
Other		(948)		(1,592)
Net deferred tax asset	$	26,449	$	31,097

As of December 31, 2015 and 2016, the Company’s liabilities for unrecognized tax benefits are included in income taxes payable in the consolidated balance sheets. Interest and penalties, including those related to uncertain tax positions, are included in the provision for income taxes in the consolidated statements of income. The Company recognized $0.1 million of expense in 2015 and 2016, related to interest and penalties. The total amount of interest and penalties included in the consolidated balance sheets was $0.2 million and $0.1 million as of December 31, 2015 and 2016, respectively.

The following table summarizes changes in unrecognized tax benefits, excluding interest and penalties, for the respective periods (in thousands):


	Year Ended December 31,
	2015		2016
Beginning unrecognized tax benefits	$	2,936	$	505
Reductions for tax positions taken in prior years		(2,431)		(329)
Ending unrecognized tax benefits	$	505	$	176

It is reasonably possible that approximately $0.1 million of unrecognized tax benefits will be reduced in the next twelve months due to expiration of the applicable statutes of limitations. The Company does not anticipate significant changes to other unrecognized tax benefits.

As of December 31, 2016, $0.2 million of the Company’s total unrecognized tax benefits would favorably affect the Company’s effective tax rate if recognized. If amounts accrued are less than amounts ultimately assessed by taxing authorities, the Company would record additional income tax expense.

A reconciliation between the Company’s statutory tax rate and the effective tax rate for the years ended December 31, 2014, 2015, and 2016 is as follows:


	2014		2015		2016
Statutory federal rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal benefits	4.2		4.2		4.5
Other	0.3		0.3		(0.2)
Effective tax rate	39.5	%	39.5	%	39.3	%

Cash payments for income taxes were $30.8 million, $28.5 million, and $31.6 million in 2014, 2015, and 2016, respectively.