Income Taxes (Tables)

12 Months Ended

Dec. 31, 2012

Income Tax Disclosure [Abstract]

Income tax Expenses Benefit

Effective Income Tax Rate Reconciliation [Table Text Block]

The reconciliation of the federal statutory and effective income tax rates follows:

	2012		2011		2010
Federal statutory rate	35.0	%	35.0	%	35.0	%
State and local income taxes, net of federal tax effect	(0.3	)	0.7		(0.4	)
Effect of excess of percentage depletion over cost depletion	(7.3	)	(3.9	)	(2.5	)
Medicare Part D	—		—		2.2
Manufacturing production deduction	(2.2	)	(3.5	)	(1.9	)
Officers’ compensation	1.1		0.7		1.5
Adjustment to unrecognized tax benefits	(0.6	)	(3.4	)	0.8
Taxes on foreign source income	(0.1	)	(0.2	)	(1.3	)
Retiree medical expense	(2.0	)	—		—
Valuation allowance	2.0		2.5		1.6
Other items	1.1		(1.6	)	(0.4	)
Effective tax rate	26.7	%	26.3	%	34.6	%

Deferred tax assets and liabilities

Deferred tax assets and (liabilities) recorded in the Consolidated Balance Sheets consist of the following:

	December 31,
(Thousands)	2012			2011
Asset (liability)
Post-retirement benefits other than pensions	$	12,003		$	11,047
Other reserves	12,804			11,476
Environmental reserves	1,958			1,932
Inventory	4,303			3,776
Pensions	27,547			21,790
Net operating loss and credit carryforwards	5,186			5,199
Miscellaneous	357			377
Subtotal	64,158			55,597
Valuation allowance	(4,584		)	(3,917		)
Total deferred tax assets	59,574			51,680
Depreciation	(19,388		)	(21,133		)
Amortization	(7,939		)	(8,016		)
Capitalized interest expense	(195		)	(224		)
Mine development	(2,832		)	(782		)
Derivative instruments and hedging activities	(168		)	(581		)
Total deferred tax liabilities	(30,522		)	(30,736		)
Net deferred tax asset	$	29,052		$	20,944

Reconciliation of unrecognized tax benefits

A reconciliation of the Company’s unrecognized tax benefits for the year-to-date period ending December 31, 2012 is as follows:

(Thousands)	2012			2011
Balance as of January 1	$	1,969		$	2,944
Additions to tax provisions related to the current year	149			—
Additions to tax positions related to prior years	174			878
Reduction to tax positions related to prior years	(20		)	—
Lapses on statutes of limitations	(455		)	(1,853		)
Settlements	(50		)	—
Balance as of December 31	$	1,767		$	1,969