Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on Recurring Basis

As of March 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 available-for-sale:
Debt securities:
Municipal	—	72,918	72,918
Corporate	—	341,283	341,283
Foreign	—	192,663	192,663
U.S. Treasury Bonds	—	12,635	12,635
Equity securities	36,700	—	36,700
	36,700	619,499	656,199

As of December 31, 2016, financial instruments measured at fair value on a recurring basis are summarized below:

	Level 1	Level 2	Fair value measurements
	($000 omitted)
Investments available-for-sale:
Debt securities:
Municipal	—	72,432	72,432
Corporate	—	343,047	343,047
Foreign	—	167,027	167,027
U.S. Treasury Bonds	—	12,613	12,613
Equity securities	36,384	—	36,384
	36,384	595,119	631,503