Investments in debt and equity securities (Tables)

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Investments in debt securities

The total fair values of the Company's investments in debt and equity securities are detailed below:

	June 30, 2018	December 31, 2017
	($000 omitted)
Investments in:
Debt securities	637,883	671,441
Equity securities	35,450	37,914
	673,333	709,355

The amortized costs and fair values of investments in debt securities are as follows:

	June 30, 2018		December 31, 2017
	Amortized costs	Fair values	Amortized costs	Fair values
	($000 omitted)
Municipal	62,837	62,831	71,581	72,669
Corporate	347,379	342,595	351,477	357,933
Foreign	222,740	219,932	229,750	228,237
U.S. Treasury Bonds	12,947	12,525	12,838	12,602
	645,903	637,883	665,646	671,441

Investments in equity securities

The total fair values of the Company's investments in debt and equity securities are detailed below:

	June 30, 2018	December 31, 2017
	($000 omitted)
Investments in:
Debt securities	637,883	671,441
Equity securities	35,450	37,914
	673,333	709,355

Following the adoption of ASU 2016-01 discussed in Notes 1 and 3, net investment losses recognized during the three and six months ended June 30, 2018 related to investments in equity securities still held as of June 30, 2018 are calculated as follows ($000 omitted):

	June 30, 2018
	Three Months Ended		Six Months Ended
	($000 omitted)
Total net investment gains (losses) recognized on equity securities during the period	1,612		(614	)
Less: Net realized losses on equity securities sold during the period	(216	)	(238	)
Net unrealized investment gains (losses) recognized on equity securities still held	1,828		(376	)

Gross unrealized gains and losses

Gross unrealized gains and losses on investments in debt securities are as follows:

	June 30, 2018		December 31, 2017
	Gains	Losses	Gains	Losses
	($000 omitted)
Municipal	463	469	1,263	175
Corporate	2,372	7,156	6,953	497
Foreign	1,320	4,128	1,742	3,255
U.S. Treasury Bonds	1	423	—	236
	4,156	12,176	9,958	4,163

Debt securities according to contractual terms

Debt securities as of June 30, 2018 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	55,856	55,917
After one year through five years	359,043	355,605
After five years through ten years	190,383	186,494
After ten years	40,621	39,867
	645,903	637,883

Gross unrealized losses on investments and fair values of related securities

Gross unrealized losses on investments in debt securities 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 June 30, 2018, were:

	Less than 12 months		More than 12 months		Total
	Losses	Fair values	Losses	Fair values	Losses	Fair values
	($000 omitted)
Municipal	198	21,849	271	5,756	469	27,605
Corporate	6,916	268,573	240	4,755	7,156	273,328
Foreign	897	73,483	3,231	88,709	4,128	162,192
U.S. Treasury Bonds	157	5,732	266	6,686	423	12,418
	8,168	369,637	4,008	105,906	12,176	475,543

Gross unrealized losses on investments in debt securities 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, 2017, were:

	Less than 12 months		More than 12 months		Total
	Losses	Fair values	Losses	Fair values	Losses	Fair values
	($000 omitted)
Municipal	58	17,023	117	5,784	175	22,807
Corporate	386	81,632	111	4,926	497	86,558
Foreign	1,528	116,130	1,727	39,031	3,255	155,161
U.S. Treasury Bonds	53	5,830	183	6,772	236	12,602
	2,025	220,615	2,138	56,513	4,163	277,128