Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Taxes

Schedule of components of provision (benefit) for income taxes

Years ended December 31,	2015			2014		2013
(in thousands)
Current (benefit) provision:
Federal	$	(24,727	)	$	119,074	$	104,890
State		(3,638	)		19,858		15,627
Foreign		7,898			2,907		1,918
Deferred (benefit) provision:
Federal		(31,178	)		11,514		(12,025	)
State		(1,835	)		840		(1,035	)
Total income tax (benefit) provision	$	(53,480	)	$	154,193	$	109,375

Schedule of reconciliation between the federal statutory rate and effective tax rate

Years ended December 31,	2015			2014			2013
Federal statutory rate		35.0	%		35.0	%		35.0	%
State income taxes, net of federal benefit		—			3.3			3.8
Tax credits		0.3			(0.7	)		(0.3	)
Non-deductible expenses		(1.3	)		0.4			0.5
Other		0.9			0.6			0.6
Effective tax rate		34.9	%		38.6	%		39.6	%

Schedule of deferred tax assets and liabilities

December 31,	2015			2014
(in thousands)
Deferred tax assets:
Self-insurance	$	7,274		$	7,675
Pension		12,048			12,555
State net operating loss carry forwards		370			451
Bad debts		4,041			5,755
Accrued payroll		1,330			2,833
Stock-based compensation		5,885			5,583
All others		4,704			2,121
Valuation allowance		(276	)		(2	)
Gross deferred tax assets		35,376			36,971
Deferred tax liabilities:
Depreciation		(137,606	)		(172,813	)
Goodwill amortization		(8,887	)		(7,974	)
All others		(4,378	)		(3,739	)
Gross deferred tax liabilities		(150,871	)		(184,526	)
Net deferred tax liabilities	$	(115,495	)	$	(147,555	)

Schedule of reconciliation of the beginning and ending amount of unrecognized tax benefits

	2015		2014
Balance at January 1	$	23,267,000	$	16,345,000
Additions based on tax positions related to the current year		2,171,000		5,193,000
Additions for tax positions of prior years		714,000		1,729,000
Balance at December 31	$	26,152,000	$	23,267,000