Employee Share-Based Incentive Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

The following table presents performance share activity for the years ended December 31, 2017, 2016 and 2015 for performance shares granted under the WTM Incentive Plan:



	Year Ended December 31,
	2017					2016					2015
$ in millions	Target Performance Shares Outstanding		Accrued Expense			Target Performance Shares Outstanding		Accrued Expense			Target Performance Shares Outstanding		Accrued Expense
Beginning of period	80,353		$	42.4		93,654		$	57.7		111,257		$	44.4
Shares paid or expired ⁽¹⁾	(30,838	)	(21.9		)	(36,294	)	(41.0		)	(42,959	)	(30.8		)
New grants	17,710		—			22,615		—			29,195		—
Forfeitures ⁽²⁾	(16,710	)	(9.3		)	378		.5			(3,839	)	(.3		)
Expense recognized	—		34.6			—		25.2			—		44.4
End of period ⁽³⁾	50,515		$	45.8		80,353		$	42.4		93,654		$	57.7


⁽¹⁾	WTM performance share payments in 2017 for the 2014-2016 performance cycle, which were paid in March 2017 ranged from 34% to 76% of target. WTM performance shares payments in 2016 for the 2013-2015 performance cycle ranged from 140% to 142% of target. WTM performance shares payments in 2015 for the 2012-2014 performance cycle ranged from 91% to 145.5% of target.


⁽²⁾	Amounts include changes in assumed forfeitures, as required under GAAP.


⁽³⁾	Outstanding performance share awards as of December 31, 2017, 2016 and 2015 exclude 2,195, 7,315 and 10,826 unvested performance shares awards for employees of Sirius Group.

Summary of performance shares outstanding and accrued expense for performance shares awarded under an Incentive Plan

following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of December 31, 2017 for each performance cycle:



$ in millions	Target WTM Performance Shares Outstanding		Accrued Expense
Performance cycle:
2017 – 2019	16,680		$	8.3
2016 – 2018	16,235		14.7
2015 – 2017	18,370		23.6
Sub-total	51,285		46.6
Assumed forfeitures	(770	)	(.8		)
Total	50,515		$	45.8

Schedule of Nonvested Restricted Stock Activity

The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the years ended December 31, 2017, 2016 and 2015:



	Year Ended December 31,
	2017					2016					2015
$ in millions	Restricted Shares		Unamortized Issue Date Fair Value			Restricted Shares		Unamortized Issue Date Fair Value			Restricted Shares		Unamortized Issue Date Fair Value
Non-vested,
Beginning of period	70,620		$	19.7		70,675		$	15.7		83,314		$	14.3
Issued	17,985		16.3			25,365		20.2			23,640		15.7
Vested	(28,846	)	—			(24,620	)	—			(36,279	)	—
Forfeited	(6,004	)	(3.5		)	(800	)	(.3		)	—		—
Expense recognized	—		(18.2		)	—		(15.9		)	—		(14.3		)
End of period ⁽¹⁾	53,755		$	14.3		70,620		$	19.7		70,675		$	15.7


⁽¹⁾	Outstanding restricted share awards as of December 31, 2017, 2016 and 2015 include 2,195, 5,235, and 9,205 unvested restricted shares for employees of Sirius Group.