Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on Recurring Basis

As of September 30, 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	—	67,106	67,106
Corporate	—	289,536	289,536
Foreign	—	153,334	153,334
U.S. Treasury Bonds	—	14,061	14,061
Equity securities	29,455	—	29,455
	29,455	524,037	553,492

As of December 31, 2014, 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	—	61,689	61,689
Corporate	—	308,691	308,691
Foreign	—	166,685	166,685
U.S. Treasury Bonds	—	14,802	14,802
Equity securities	28,236	—	28,236
	28,236	551,867	580,103