Investments in debt and equity securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Amortized Costs and Fair Values

Amortized costs and fair values at December 31, follow:

	2016		2015
	Amortized costs	Fair values	Amortized costs	Fair values
	($000 omitted)
Debt securities:
Municipal	72,284	72,432	70,300	72,008
Corporate	338,365	343,047	303,870	309,461
Foreign	165,735	167,027	149,914	153,221
U.S. Treasury Bonds	12,795	12,613	13,803	13,906
Equity securities	30,255	36,384	27,497	31,253
	619,434	631,503	565,384	579,849

Gross Unrealized Gains and Losses

Gross unrealized gains and losses at December 31, were:

	2016		2015
	Gains	Losses	Gains	Losses
	($000 omitted)
Debt securities:
Municipal	723	575	1,720	12
Corporate	6,871	2,189	7,700	2,109
Foreign	2,912	1,620	3,789	482
U.S. Treasury Bonds	4	186	128	25
Equity securities	6,800	671	4,842	1,086
	17,310	5,241	18,179	3,714

Debt Securities According to Contractual Terms

Debt securities at December 31, 2016 mature, according to their contractual terms, as follows (actual maturities may differ due to call or prepayment rights):

	Amortized costs	Fair values
	($000 omitted)
In one year or less	53,313	53,644
After one year through five years	227,877	232,594
After five years through ten years	225,206	225,483
After ten years	82,783	83,398
	589,179	595,119

Gross Unrealized Losses on Investments and Fair Values of Related Securities

Gross unrealized losses on investments and the fair values of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2016, were:

	Less than 12 months		More than 12 months		Total
	Losses	Fair values	Losses	Fair values	Losses	Fair values
	($000 omitted)
Debt securities:
Municipal	575	32,038	—	—	575	32,038
Corporate	2,189	119,965	—	—	2,189	119,965
Foreign	1,427	70,012	193	3,160	1,620	73,172
U.S. Treasury Bonds	186	11,847	—	—	186	11,847
Equity securities:	424	5,950	247	2,250	671	8,200
	4,801	239,812	440	5,410	5,241	245,222

Gross unrealized losses on investments and the fair values of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2015, were:

	Less than 12 months		More than 12 months		Total
	Losses	Fair values	Losses	Fair values	Losses	Fair values
	($000 omitted)
Debt securities:
Municipal	9	2,230	3	1,615	12	3,845
Corporate	1,461	83,565	648	32,871	2,109	116,436
Foreign	322	35,008	160	3,155	482	38,163
U.S. Treasury Bonds	6	1,195	19	3,583	25	4,778
Equity securities:	720	4,440	366	3,224	1,086	7,664
	2,518	126,438	1,196	44,448	3,714	170,886