INCOME TAXES

Income tax expense consisted of the following (in thousands):



	Years Ended December 31,
	2015		2014		2013
Current:
Federal	$	32,090	$	51,260	$	55,227
State	5,665		6,606		6,616
Foreign	1,250		220		1,472
	39,005		58,086		63,315
Deferred:
Federal	33,912		4,503		(9,668		)
State	4,530		535		1,279
	38,442		5,038		(8,389		)
Total income tax expense	$	77,447	$	63,124	$	54,926

The effective income tax rate differs from the federal corporate tax rate of 35% in 2015, 2014 and 2013 as follows (in thousands):



	Years Ended December 31,
	2015			2014			2013
Tax at statutory rate	$	70,406		$	56,621		$	49,599
State income taxes, net of federal tax benefits	6,627			4,641			5,132
Non-deductible meals and entertainment	1,687			1,497			1,577
Income tax credits	(1,700		)	(1,600		)	(1,574		)
Other, net	427			1,965			192
Total income tax expense	$	77,447		$	63,124		$	54,926

At December 31, deferred tax assets and liabilities consisted of the following (in thousands):



	December 31,
	2015		2014
Deferred tax assets:
Insurance and claims accruals	$	71,285	$	74,651
Allowance for uncollectible accounts	6,138		8,260
Other	16,478		14,724
Gross deferred tax assets	93,901		97,635
Deferred tax liabilities:
Property and equipment	330,580		295,628
Prepaid expenses	7,229		6,913
Other	2,356		2,634
Gross deferred tax liabilities	340,165		305,175
Net deferred tax liability	$	246,264	$	207,540

These amounts are presented in the accompanying Consolidated Balance Sheets as of December 31 as follows (in thousands):



	December 31,
	2015		2014
Current deferred tax asset	$	28,037	$	34,066
Non-current deferred tax liability	274,301		241,606
Net deferred tax liability	$	246,264	$	207,540

We have not recorded a valuation allowance because we believe that all deferred tax assets are more likely than not to be realized as a result of our historical profitability, future taxable income and reversal of deferred tax liabilities.

We recognized a $551 thousand decrease in the net liability for unrecognized tax benefits for the year ended December 31, 2015 and a $37 thousand decrease for the year ended December 31, 2014. We accrued interest expense of $0.2 million during 2015 and $0.2 million during 2014, excluding from both years the reversal of accrued interest related to the adjustment of uncertain tax positions. If recognized, $5.0 million of unrecognized tax benefits as of December 31, 2015 and $5.5 million as of December 31, 2014 would impact our effective tax rate. Interest of $1.4 million as of December 31, 2015 and $1.7 million as of December 31, 2014 has been reflected as a component of the total liability. We expect no other significant increases or decreases for uncertain tax positions during the next twelve months.

The reconciliations of beginning and ending gross balances of unrecognized tax benefits for 2015 and 2014 are shown below (in thousands).



	December 31,
	2015			2014
Unrecognized tax benefits, beginning balance	$	8,583		$	8,644
Gross increases – tax positions in prior period	229			244
Gross increases – current-period tax positions	769			745
Settlements	(1,864		)	(1,050		)
Unrecognized tax benefits, ending balance	$	7,717		$	8,583

We file U.S. federal income tax returns, as well as income tax returns in various states and several foreign jurisdictions. The years 2011 through 2014 are open for examination by the U.S. Internal Revenue Service (“IRS”), and various years are open for examination by state and foreign tax authorities. In December 2015, we were notified that the IRS will perform an audit of our amended 2011 federal income tax return. State and foreign jurisdictional statutes of limitations generally range from three to four years.