Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Available-for-sale securities

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

September 30, 2018	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	10,550	$	3	$	251	$	10,302
U.S. Treasury securities	179		—		—		179
Total	$	10,729	$	3	$	251	$	10,481

September 30, 2017	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	9,488	$	11	$	72	$	9,427
U.S. Treasury securities	613		—		1		612
Total	$	10,101	$	11	$	73	$	10,039

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 September 30, 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 September 30, 2018
	(In thousands)
Assets:
Money market funds	$	—	$	9,948	$	—	$	9,948
Insurance contract*	—		80,358		—		80,358
Available-for-sale securities:
Mortgage-backed securities	—		10,302		—		10,302
U.S. Treasury securities	—		179		—		179
Total assets measured at fair value	$	—	$	100,787	$	—	$	100,787

* The insurance contract invests approximately 47 percent in fixed-income investments, 24 percent in common stock of large-cap companies, 13 percent in common stock of mid-cap companies, 12 percent in common stock of small-cap companies, 3 percent in target date investments and 1 percent in cash equivalents.

	Fair Value Measurements at September 30, 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 September 30, 2017
	(In thousands)
Assets:
Money market funds	$	—	$	6,204	$	—	$	6,204
Insurance contract*	—		74,991		—		74,991
Available-for-sale securities:
Mortgage-backed securities	—		9,427		—		9,427
U.S. Treasury securities	—		612		—		612
Total assets measured at fair value	$	—	$	91,234	$	—	$	91,234

* The insurance contract invests approximately 50 percent in fixed-income investments, 23 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 September 30, 2018	$	1,915,470	$	1,987,360
Long-term debt at September 30, 2017	$	1,740,552	$	1,846,811
Long-term debt at December 31, 2017	$	1,714,853	$	1,826,256