Income taxes (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Income Taxes

Summarized below are (i) the differences between the provision for income taxes and the amounts that would be expected using the U. S. federal statutory income tax rate of 35%, and (ii) the components of the comprehensive provision for income taxes.

	Years ended December 31,
	2010			2011			2012
	(In thousands)
Expected tax provision, at statutory rate	$	7,231		$	17,868		$	11,257
U.S. state income taxes, net		1,372			3,298			1,036
Other, net		42			(328	)		(350	)
Provision for income taxes	$	8,645		$	20,838		$	11,943
Provision for income taxes:
Currently payable:
U.S. federal	$	1,984		$	8,800		$	5,002
U.S. state		108			1,562			896
Net currently payable		2,092			10,362			5,898
Deferred income taxes, net		6,553			10,476			6,045
Provision for income taxes	$	8,645		$	20,838		$	11,943
Comprehensive provision for income taxes allocable to:
Net income	$	8,645		$	20,838		$	11,943
Other comprehensive income (loss):
Pension plans		25,771			(49,721	)		8,151
OPEB plans		(3,980	)		(5,890	)		(4,920	)
Additional paid-in capital:
Retirement of treasury stock		—			456			—
Transactions with stockholders		—			106			—
	$	30,436		$	(34,211	)	$	15,174

Schedule of Net Deferred Tax Asset and Liability

The components of the net deferred tax asset/(liability) are summarized below.

	December 31,
	2011						2012
	Assets			Liabilities			Assets			Liabilities
	(In thousands)
Tax effect of temporary differences relating to:
Inventories	$	4,587		$	—		$	5,859		$	—
Property and equipment		—			(18,612	)		—			(20,246	)
Pension asset		—			(28,197	)		—			(40,323	)
Accrued pension cost		8,430			—			11,036			—
Accrued OPEB cost		20,445			—			21,454			—
Accrued employee benefits		5,604			—			5,825			—
Accrued insurance		1,389			—			1,066			—
Other accrued liabilities		555			—			226			—
Other deductible differences		210			—			236			—
Gross deferred tax assets / (liabilities)		41,220			(46,809	)		45,702			(60,569	)
Reclassification, principally netting by tax jurisdiction		(29,026	)		29,026			(32,862	)		32,862
Net deferred tax asset / (liability)		12,194			(17,783	)		12,840			(27,707	)
Less current deferred tax asset		(12,194	)		—			(12,840	)		—
Noncurrent deferred tax liability	$	—		$	(17,783	)	$	—		$	(27,707	)