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:

	2016		2015
Deferred tax assets:
Employee benefits	$	1,349	$	1,296
Inventories		8,811		7,071
Natural gas derivatives		1,281		4,183
Goodwill & other intangibles		4,881		3,980
Net operating loss		51,722		39,360
Other		2,027		1,723
Foreign losses		—		1,230
Foreign tax assets valuation allowance		—		(1,230	)
Total deferred tax assets		70,071		57,613
Deferred tax liabilities:
Depreciation		71,308		71,976
Total deferred tax liabilities		71,308		71,976
Net deferred tax liabilities	$	1,237	$	14,363

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

	2016			2015			2014
Current:
Federal	$	(495	)	$	1,509		$	11,310
State		(496	)		120			500
Foreign		445			966			1,084
Total current		(546	)		2,595			12,894
Deferred		(50,535	)		(56,800	)		24,389
	$	(51,081	)	$	(54,205	)	$	37,283

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:

	2016						2015						2014
	Amount			Percent			Amount			Percent			Amount			Percent
U.S. statutory rate	$	(45,923	)		(35.0	)%	$	(57,312	)		(35.0	)%	$	32,505			35.0	%
State income taxes, net of federal tax benefit		(3,283	)		(2.5	)		(3,474	)		(2.1	)		1,882			2.0
Mining depletion		(378	)		(0.3	)		(1,557	)		(0.9	)		(3,035	)		(3.3	)
Change in election for foreign tax credits		(2,753	)		(2.1	)		1,442			0.9			—			—
Foreign tax assets valuation allowance		—			—			1,230			0.7			4,300			4.6
Foreign investments		(323	)		(0.2	)		847			0.5			2,980			3.2
Stock compensation excess tax deficiency		789			0.6			—			—			—			—
Other permanent differences		790			0.6			4,619			2.8			(1,349	)		(1.4	)
	$	(51,081	)		(38.9	)%	$	(54,205	)		(33.1	)%	$	37,283			40.1	%

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 year ended December 31, 2016, the Company adjusted the DTL associated with its foreign investments which resulted in an additional benefit of $323. During the year ended December 31, 2015, the Company did not recognize benefits on foreign investments of $847 and recorded a valuation allowance of $1,230 due to the uncertainty of the Company being able to realize the foreign tax assets in light of current market conditions in China. During 2016, there was no change to this foreign valuation allowance.

During 2016 and 2015, the Company incurred a net operating loss in the United States. The tax benefit of these net operating losses totals $51,722 and $39,360, respectively, and is included in the deferred income tax asset. The Company filed amended 2013 and 2014 Federal income tax returns to claim $37,397 of the tax benefit which was received as a refund in April 2016. After finalization of the 2015 Federal return and a change in the attribute of the NOL carryback, additional refunds for 2012 through 2014 tax years are being claimed in the amount of $1,732. These amounts are included within deferred tax assets as of December 31, 2016. The federal NOLs generated in 2016 will be carried forward until they are utilized or their expiration in 2036.

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. No such bonus depreciation is anticipated for 2016.

The Company has not recognized any uncertain tax positions as of December 31, 2016. The reserve recorded as of December 31, 2015 of $153 was associated with a period no longer subject to audit and thus was reduced to $0 during 2016.

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. In 2016, the Company received an audit notice from the Internal Revenue Service for periods 2013-2015. The Company does not anticipate any material findings. Various U.S. state jurisdiction tax years remain open to examination as well, although the Company believes assessments, if any, would be immaterial to its consolidated financial statements.