Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Financial instruments measured at fair value on recurring basis

As of September 30, 2018, financial instruments measured at fair value on a recurring basis are summarized below:

	Level 1	Level 2	Fair value measurements
	($000 omitted)
Investments in securities:
Debt securities:
Municipal	—	61,703	61,703
Corporate	—	340,919	340,919
Foreign	—	209,329	209,329
U.S. Treasury Bonds	—	12,471	12,471
Equity securities	37,667	—	37,667
	37,667	624,422	662,089

As of December 31, 2017, financial instruments measured at fair value on a recurring basis are summarized below:

	Level 1	Level 2	Fair value measurements
	($000 omitted)
Investments in securities:
Debt securities:
Municipal	—	72,669	72,669
Corporate	—	357,933	357,933
Foreign	—	228,237	228,237
U.S. Treasury Bonds	—	12,602	12,602
Equity securities	37,914	—	37,914
	37,914	671,441	709,355