Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Available-for-sale securities

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

March 31, 2018	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	10,282	$	4	$	223	$	10,063
U.S. Treasury securities	466		—		1		465
Total	$	10,748	$	4	$	224	$	10,528

March 31, 2017	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	9,971	$	8	$	94	$	9,885
U.S. Treasury securities	412		1		—		413
Total	$	10,383	$	9	$	94	$	10,298

December 31, 2017	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	10,342	$	4	$	129	$	10,217
U.S. Treasury securities	205		—		1		204
Total	$	10,547	$	4	$	130	$	10,421

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, 2018, 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, 2018
	(In thousands)
Assets:
Money market funds	$	—	$	9,085	$	—	$	9,085
Insurance contract*	—		76,941		—		76,941
Available-for-sale securities:
Mortgage-backed securities	—		10,063		—		10,063
U.S. Treasury securities	—		465		—		465
Total assets measured at fair value	$	—	$	96,554	$	—	$	96,554

* The insurance contract invests approximately 49 percent in fixed-income investments, 22 percent in common stock of large-cap companies, 13 percent in common stock of mid-cap companies, 11 percent in common stock of small-cap companies, 3 percent in target date investments and 2 percent in cash equivalents.

	Fair Value Measurements at March 31, 2017, 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, 2017
	(In thousands)
Assets:
Money market funds	$	—	$	2,551	$	—	$	2,551
Insurance contract*	—		73,775		—		73,775
Available-for-sale securities:
Mortgage-backed securities	—		9,885		—		9,885
U.S. Treasury securities	—		413		—		413
Total assets measured at fair value	$	—	$	86,624	$	—	$	86,624

* The insurance contract invests approximately 51 percent in fixed-income investments, 22 percent in common stock of large-cap companies, 13 percent in common stock of mid-cap companies, 11 percent in common stock of small-cap companies, 2 percent in target date investments and 1 percent in cash equivalents.

	Fair Value Measurements at December 31, 2017, 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, 2017
	(In thousands)
Assets:
Money market funds	$	—	$	6,965	$	—	$	6,965
Insurance contract*	—		77,388		—		77,388
Available-for-sale securities:
Mortgage-backed securities	—		10,217		—		10,217
U.S. Treasury securities	—		204		—		204
Total assets measured at fair value	$	—	$	94,774	$	—	$	94,774

* The insurance contract invests approximately 49 percent in fixed-income investments, 23 percent in common stock of large-cap companies, 14 percent in common stock of mid-cap companies, 11 percent in common stock of small-cap companies, 2 percent in target date 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, 2018	$	1,779,542	$	1,854,350
Long-term debt at March 31, 2017	$	1,703,006	$	1,784,588
Long-term debt at December 31, 2017	$	1,714,853	$	1,826,256