Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Income tax expense (benefit)

Income tax expense consists of:

	Years Ended December 31,
	2015			2014			2013
	(in thousands)
Current:
Federal	$	11,322		$	(10,569	)	$	9,379
State and local	3,587			3,100			3,134
Foreign	738			174			353
Total current	15,647			(7,295		)	12,866
Deferred
Federal	56,431			63,577			33,842
State and local	5,221			8,804			5,725
Foreign	(8		)	(12		)	7
Total deferred	61,644			72,369			39,574
Total income tax expense	$	77,291		$	65,074		$	52,440

Summary of Federal statutory income tax rate attributable to earnings (loss) from operations

The reconciliation of income taxes computed at the United States federal statutory tax rate to income tax expense is: 

	Years Ended December 31,
	2015			2014		2013
	(in thousands)
Computed income tax expense	$	73,760		$	57,612	$	48,768
State and local tax expense	4,207			6,709		5,544
Permanent differences, including domestic production activities deduction	(724		)	523		(626		)
Adjustments for uncertain tax positions	204			206		(166		)
Other, net	(156		)	24		(1,080		)
Total income tax expense	$	77,291		$	65,074	$	52,440

Summary of deferred tax assets and liabilities

The net deferred tax asset (liability) is classified in the consolidated balance sheets as follows: 

	December 31,
	2015			2014
	(in thousands)
Current deferred tax assets	$	—		$	7,688
Non-current deferred tax assets	14,076			5,482
Non-current deferred tax liability	(236,414		)	(173,831		)
Non-current deferred tax liability, net	(222,338		)	(168,349		)
Current deferred tax asset	—			7,688
Non-current deferred tax liability, net	(222,338		)	(168,349		)
Net deferred tax liability	$	(222,338	)	$	(160,661	)

The tax effects of temporary differences that have given rise to deferred tax assets and liabilities are presented below: 

	December 31,
	2015			2014
	(in thousands)
Current deferred tax assets
Provisions not currently deductible	$	—		$	7,234
Tax credits and other	—			246
Net operating loss —state	—			208
Total current deferred tax asset	—			7,688
Non-current deferred tax assets
Provisions not currently deductible	8,192			392
Stock based compensation	110			136
Net operating loss carryforwards—federal and state	173			—
Net capital loss carryforwards—federal and state	1,859			1,859
Tax credits and other	519			—
Pensions and post retirement	3,223			3,095
Total non-current deferred tax asset	14,076			5,482
Total deferred tax asset	$	14,076		$	13,170
Non-current deferred tax liabilities
Investment in joint ventures/partnerships	$	(2,056	)	$	(2,269	)
Property, plant and equipment	(234,358		)	(171,562		)
Total deferred tax liability	$	(236,414	)	$	(173,831	)

Summary of changes in the balance of unrecognized tax benefits

The aggregate changes in the balance of unrecognized tax benefits were as follows: 

	Years Ended December 31,
	2015			2014		2013
	(in thousands)
Beginning balance	$	1,422		$	1,142	$	1,744
Increases in tax positions for prior years	30			91		53
Increases in tax positions for current year	298			189		103
Settlements and decreases in tax positions	(66		)	—		(716		)
Expirations of statutes	—			—		(42		)
Ending balance	$	1,684		$	1,422	$	1,142