Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Available-for-sale securities

Details of available-for-sale securities were as follows:

March 31, 2015	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Mortgage-backed securities	$	7,792	$	58	$	(18	)	$	7,832
U.S. Treasury securities	2,337		9		(4		)	2,342
Total	$	10,129	$	67	$	(22	)	$	10,174

March 31, 2014	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Mortgage-backed securities	$	7,943	$	63	$	(17	)	$	7,989
U.S. Treasury securities	2,069		9		—			2,078
Total	$	10,012	$	72	$	(17	)	$	10,067

December 31, 2014	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Mortgage-backed securities	$	6,594	$	60	$	(18	)	$	6,636
U.S. Treasury securities	3,574		—		(19		)	3,555
Total	$	10,168	$	60	$	(37	)	$	10,191

Assets and liabilities measured at fair value on a recurring basis

The Company's assets and liabilities measured at fair value on a recurring basis were as follows:

	Fair Value Measurements at March 31, 2015, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at March 31, 2015
	(In thousands)
Assets:
Money market funds	$	—	$	16,945	$	—	$	16,945
Insurance contract*	—		67,797		—		67,797
Available-for-sale securities:
Mortgage-backed securities	—		7,832		—		7,832
U.S. Treasury securities	—		2,342		—		2,342
Commodity derivative instruments	—		7,127		—		7,127
Total assets measured at fair value	$	—	$	102,043	$	—	$	102,043

* The insurance contract invests approximately 20 percent in common stock of mid-cap companies, 18 percent in common stock of small-cap companies, 28 percent in common stock of large-cap companies, 32 percent in fixed-income investments, 1 percent in target date investments and 1 percent in cash equivalents.

	Fair Value Measurements at March 31, 2014, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at March 31, 2014
	(In thousands)
Assets:
Money market funds	$	—	$	20,267	$	—	$	20,267
Insurance contract*	—		63,269		—		63,269
Available-for-sale securities:
Mortgage-backed securities	—		7,989		—		7,989
U.S. Treasury securities	—		2,078		—		2,078
Commodity derivative instruments	—		330		—		330
Total assets measured at fair value	$	—	$	93,933	$	—	$	93,933
Liabilities:
Commodity derivative instruments	$	—	$	12,186	$	—	$	12,186
Total liabilities measured at fair value	$	—	$	12,186	$	—	$	12,186

* The insurance contract invests approximately 29 percent in common stock of mid-cap companies, 27 percent in common stock of small-cap companies, 28 percent in common stock of large-cap companies and 16 percent in fixed-income investments.

	Fair Value Measurements at December 31, 2014, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs  (Level 3)		Balance at December 31, 2014
	(In thousands)
Assets:
Money market funds	$	—	$	18,473	$	—	$	18,473
Insurance contract*	—		65,831		—		65,831
Available-for-sale securities:
Mortgage-backed securities	—		6,636		—		6,636
U.S. Treasury securities	—		3,555		—		3,555
Commodity derivative instruments	—		18,335		—		18,335
Total assets measured at fair value	$	—	$	112,830	$	—	$	112,830

* The insurance contract invests approximately 20 percent in common stock of mid-cap companies, 18 percent in common stock of small-cap companies, 29 percent in common stock of large-cap companies, 32 percent in fixed-income investments and 1 percent in cash equivalents.

Fair value of long term debt outstanding

The estimated fair value of the Company's Level 2 long-term debt was as follows:

	Carrying Amount		Fair Value
	(In thousands)
Long-term debt at March 31, 2015	$	2,189,986	$	2,340,681
Long-term debt at March 31, 2014	$	2,105,832	$	2,186,839
Long-term debt at December 31, 2014	$	2,094,727	$	2,239,445