Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2016

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on Recurring Basis

As of September 30, 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	—	75,421	75,421
Corporate	—	358,164	358,164
Foreign	—	162,798	162,798
U.S. Treasury Bonds	—	12,883	12,883
Equity securities	34,425	—	34,425
	34,425	609,266	643,691

As of December 31, 2015, 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	—	72,008	72,008
Corporate	—	309,461	309,461
Foreign	—	153,221	153,221
U.S. Treasury Bonds	—	13,906	13,906
Equity securities	31,253	—	31,253
	31,253	548,596	579,849