Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2016

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on Recurring Basis

As of June 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	—	73,492	73,492
Corporate	—	351,069	351,069
Foreign	—	164,255	164,255
U.S. Treasury Bonds	—	12,946	12,946
Equity securities	34,286	—	34,286
	34,286	601,762	636,048

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