Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

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

Summary of Stock Option Plans

A summary of activity under United’s stock option plans as of March 31, 2020, and the changes during the first three months of 2020 are presented below:

	Three Months Ended March 31, 2020
						Weighted Average
				Aggregate		Remaining
				Intrinsic		Contractual		Exercise
	Shares			Value		Term (Yrs.)		Price
Outstanding at January 1, 2020		1,715,316						$	34.49
Granted		183,551							32.51
Exercised		(14,694	)						20.31
Forfeited or expired		(6,088	)						27.31
Outstanding at March 31, 2020		1,878,085		$	174,324		5.8	$	34.43
Exercisable at March 31, 2020		1,332,280		$	174,324		4.6	$	33.37

Status of United's Nonvested Stock Option Awards

The following table summarizes the status of United’s nonvested stock option awards during the first three months of 2020:

	Shares			Weighted-Average Grant Date Fair Value Per Share
Nonvested at January 1, 2020		589,737		$	7.62
Granted		183,551			5.65
Vested		(225,132	)		7.68
Forfeited or expired		(2,351	)		7.32
Nonvested at March 31, 2020		545,805		$	6.94

Changes to United's Restricted Common Shares

The following summarizes the changes to United’s restricted common shares for the period ended March 31, 2020:

	Number of Shares			Weighted-Average Grant Date Fair Value Per Share
Outstanding at January 1, 2020		247,896		$	39.20
Granted		175,495			32.51
Vested		(88,545	)		39.32
Forfeited		(946	)		36.58
Outstanding at March 31, 2020		333,900		$	35.66