Share-Based Payments (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Summary of compensation expense and related tax benefit recognized during each period, and compensation cost expense in future periods

The following table provides a summary of compensation expense and the total related tax benefit recognized during each period as well as estimated compensation cost that will be charged to expense in future periods.

	Share-Based Compensation Expense						Unrecognized Compensation Cost
	Year Ended December 31						December 31, 2019
($ in millions, except remaining recognition period)	2019		2018		2017		Amount		Weighted Average Remaining Recognition Period
Total share-based compensation expense	$	3.5	$	5.3	$	10.6	$	5.6	2.5
Tax benefit recognized	$	0.7	$	1.1	$	3.7

Summary of activity related to management share awards

Activity for restricted share units during 2019, 2018 and 2017 is summarized below. Grant date fair values are based on the market value of a share of ProAssurance common stock on the date of grant less the estimated net present value of expected dividends during the vesting period.

	2019				2018				2017
	Units		Weighted Average Grant Date Fair Value		Units		Weighted Average Grant Date Fair Value		Units		Weighted Average Grant Date Fair Value
Beginning non-vested balance	267,323		$	49.16	269,520		$	48.63	240,149		$	44.07
Granted	164,196		$	36.96	85,797		$	44.73	84,565		$	58.35
Forfeited	(3,832	)	$	45.09	(3,878	)	$	50.07	(4,087	)	$	52.35
Vested and released	(107,062	)	$	46.06	(84,116	)	$	42.90	(51,107	)	$	43.01
Ending non-vested balance	320,625		$	43.99	267,323		$	49.16	269,520		$	48.63

Summary of activity for performance share awards

The table reflects the base number of units; actual awards that vest depend upon the extent to which performance objectives are achieved. Grant date fair values are based on the market value of a share of ProAssurance common stock on the date of grant less the estimated net present value of expected dividends during the vesting period.

	2019				2018				2017
	Base Units		Weighted Average Grant Date Fair Value		Base Units		Weighted Average Grant Date Fair Value		Base Units		Weighted Average Grant Date Fair Value
Beginning non-vested balance	135,202		$	49.95	212,105		$	47.11	305,240		$	43.41
Granted	25,168		$	40.18	27,202		$	44.73	48,000		$	58.35
Forfeited	—		$	—	—		$	—	(227	)	$	42.79
Vested and released	(60,000	)	$	45.59	(104,105	)	$	42.79	(140,908	)	$	42.95
Ending non-vested balance	100,370		$	50.10	135,202		$	49.95	212,105		$	47.11

Summary of market value of ProAssurance common share on the grant date fair value

Purchase match unit activity during 2019, 2018 and 2017 is summarized below. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant less the estimated net present value of expected dividends during the vesting period.

	2019				2018				2017
	Units		Weighted Average Grant Date Fair Value		Units		Weighted Average Grant Date Fair Value		Units		Weighted Average Grant Date Fair Value
Beginning non-vested balance	44,682		$	51.05	70,292		$	49.40	72,615		$	45.77
Granted	—		$	—	—		$	—	24,444		$	51.83
Forfeited	(1,400	)	$	51.47	(1,594	)	$	50.19	(2,012	)	$	48.29
Vested and released	(43,282	)	$	51.03	(24,016	)	$	46.28	(24,755	)	$	41.33
Ending non-vested balance	—		$	—	44,682		$	51.05	70,292		$	49.40