Investments in debt and equity securities (Tables)

9 Months Ended

Sep. 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:

	September 30, 2018	December 31, 2017
	($000 omitted)
Investments in:
Debt securities	624,422	671,441
Equity securities	37,667	37,914
	662,089	709,355

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

	September 30, 2018		December 31, 2017
	Amortized costs	Fair values	Amortized costs	Fair values
	($000 omitted)
Municipal	62,097	61,703	71,581	72,669
Corporate	346,429	340,919	351,477	357,933
Foreign	213,559	209,329	229,750	228,237
U.S. Treasury Bonds	12,948	12,471	12,838	12,602
	635,033	624,422	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:

	September 30, 2018	December 31, 2017
	($000 omitted)
Investments in:
Debt securities	624,422	671,441
Equity securities	37,667	37,914
	662,089	709,355

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

	September 30, 2018
	Three Months Ended	Nine Months Ended
	($000 omitted)
Total net investment gains recognized on equity securities during the period	2,775	2,161
Less: Net realized gains on equity securities sold during the period	598	359
Net unrealized investment gains recognized on equity securities still held	2,177	1,802

Gross unrealized gains and losses

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

	September 30, 2018		December 31, 2017
	Gains	Losses	Gains	Losses
	($000 omitted)
Municipal	261	655	1,263	175
Corporate	2,045	7,555	6,953	497
Foreign	1,115	5,345	1,742	3,255
U.S. Treasury Bonds	—	477	—	236
	3,421	14,032	9,958	4,163

Debt securities according to contractual terms

Debt securities as of September 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	48,839	48,844
After one year through five years	364,717	359,727
After five years through ten years	182,578	177,919
After ten years	38,899	37,932
	635,033	624,422

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 September 30, 2018, were:

	Less than 12 months		More than 12 months		Total
	Losses	Fair values	Losses	Fair values	Losses	Fair values
	($000 omitted)
Municipal	314	33,036	341	6,808	655	39,844
Corporate	6,862	266,231	693	15,359	7,555	281,590
Foreign	1,242	70,048	4,103	104,795	5,345	174,843
U.S. Treasury Bonds	150	4,277	327	8,088	477	12,365
	8,568	373,592	5,464	135,050	14,032	508,642

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