Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2012

Financial Instruments Measured at Fair Value on Recurring Basis

At December 31, 2012, financial instruments measured at fair value on a recurring basis are summarized below:

	Level 1		Level 2		Level 3		Fair value measurements
	($000 omitted)
Short-term investments		37,025		—		—		37,025
Investments available-for-sale:
Debt securities:
Municipal		—		19,011		—		19,011
Corporate and utilities		—		287,528		—		287,528
Foreign		—		169,009		—		169,009
U.S. Government		—		16,638		—		16,638
Equity securities:		11,073		—		—		11,073
		48,098		492,186		—		540,284

At December 31, 2011, financial instruments measured at fair value on a recurring basis are summarized below:

	Level 1		Level 2		Level 3		Fair value measurements
	($000 omitted)
Short-term investments		33,137		—		—		33,137
Investments available-for-sale:
Debt securities:
Municipal		—		27,801		—		27,801
Corporate and utilities		—		244,123		—		244,123
Foreign		—		164,268		—		164,268
U.S. Government		—		19,350		—		19,350
Equity securities:		5,443		—		—		5,443
		38,580		455,542		—		494,122

Assets Measured at Fair Value on Nonrecurring Basis

As of December 31, 2012, assets measured at fair value on a nonrecurring basis are summarized below:

	Level 3		Impairment loss recorded
	($000 omitted)
Cost-basis investments		1,640		753

As of December 31, 2011, assets measured at fair value on a nonrecurring basis are summarized below:

	Level 3		Impairment loss recorded
	($000 omitted)
Cost-basis investments		1,167		2,685