6. Income Taxes

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities as of December 31 are as follows:


	2015			2014
Deferred tax assets:
Employee benefits	$	1,296		$	1,440
Inventories		7,071			6,966
Natural gas derivatives		4,183			—
Goodwill		3,980			874
Net Operating Loss		39,360			—
Other		1,723			2,942
Foreign losses		1,230			4,300
Foreign tax assets valuation allowance		(1,230	)		(4,300	)

Total deferred tax assets		57,613			12,222

Deferred tax liabilities:
Depreciation		71,976			81,628

Total deferred tax liabilities		71,976			81,628

Net deferred tax liabilities	$	14,363		$	69,406

Significant components of the provision for income taxes for the years ended December 31 are as follows:


	2015			2014		2013
Current:
Federal	$	1,509		$	11,310	$	27,188
State		120			500		2,164
Foreign		966			1,084		842

Total current		2,595			12,894		30,194
Deferred		(56,800	)		24,389		10,121

		$(54,205)		$	37,283	$	40,315

The reconciliation of income taxes computed at the U.S. statutory tax rate to the Company’s income tax expense for the years ended December 31 is as follows:


	2015						2014						2013
	Amount			Percent			Amount			Percent			Amount			Percent
U.S. statutory rate	$	(57,312	)		(35.0	)%	$	32,505			35.0	%	$	43,820			35.0	%
State income taxes, net of federal tax benefit		(3,474	)		(2.1	)		1,882			2.0			2,097			1.7
Mining depletion		(1,557	)		(0.9	)		(3,035	)		(3.3	)		(2,751	)		(2.2	)
Change in election to deduct foreign taxes paid		1,442			0.9			—			—			—			—
Foreign tax assets valuation allowance		1,230			0.7			4,300			4.6			—			—
Non-recognized benefit on foreign investments		847			0.5			2,980			3.2			—			—
Section 199 Manufacturing Benefit and other		4,619			2.8			(1,349	)		(1.4	)		(2,851	)		(2.3	)

	$	(54,205	)		(33.1	)%	$	37,283			40.1	%	$	40,315			32.2	%

Provision has been made for deferred U.S. income taxes on all foreign earnings based on the Company’s intent to repatriate foreign earnings. During the years ended December 31, 2015 and 2014, the Company did not recognize benefits on foreign investments of $847 and $2,980, respectively, and recorded valuation allowances of $1,230 and $4,300, respectively, due to the uncertainty of the Company being able to realize the foreign tax assets in light of current market conditions in China.

During 2015, the Company incurred a net operating loss in the United States. The tax benefit of this net operating loss totals $39,360 and is included in the deferred income tax asset. The Company intends to file amended 2013 and 2014 Federal income tax returns to claim refunds and thus realize this income tax benefit. Upon filing the amended Federal tax returns, approximately $36,800 of the tax benefit will become a current income tax receivable and is expected to be refunded during the first half of 2016. Amended state income tax returns will be filed later during 2016 to claim refunds associated with carryback of net operating losses.

The Company elected to claim bonus tax depreciation totaling $29,221 and $61,781 on assets placed in service in the United States during 2015 and 2014, respectively. This election increased the net operating loss in 2015 and reduced current taxable income in 2014. The Company did not claim bonus depreciation on assets placed in service during 2013.

The Company had a recorded reserve of $153 associated with uncertain tax positions as of December 31, 2015 and there were no significant changes to the recorded reserve during 2015. If these uncertain tax positions are recognized, substantially all of this amount would impact the effective tax rate. Related accrued interest and penalties are recorded in income tax expense and are not material.

The Company files its tax returns as prescribed by the tax laws of the jurisdictions in which it operates, the most significant of which are U.S. federal and certain state jurisdictions. The 2012 and subsequent tax years are still subject to examination. Various U.S. state jurisdiction tax years remain open to examination as well though the Company believes assessments, if any, would be immaterial to its consolidated financial statements.