Accounting for Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Stock-based Compensation Expense

The total stock-based compensation expense for the years ended December 31, 2019, 2018, and 2017, the unrecognized compensation expense at December 31, 2019, and the weighted-average period to recognize the remaining unrecognized shares are as follows:

	Stock-Based Compensation Expense
	Recognized as of December 31,						Unrecognized
	2019		2018		2017		December 31, 2019		Weighted-Average Period to Recognize (years)
Stock Options	$	—	$	—	$	164	$	—		—
Restricted Stock Units		10,644		7,410		7,080		15,345		1.6
Cash-Settled Restricted Stock Units		10,213		8,214		7,253		10,400		1.7
Non-Employee Director Awards		719		764		671		328		0.4
Performance Shares		4,455		3,193		2,376		4,200		1.5
Total	$	26,031	$	19,581	$	17,544	$	30,273

Outstanding Stock Option Activity

The following table summarizes the changes in outstanding stock options:

	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at January 1, 2017		587,407		$	29.56
Exercised		(175,909	)	$	26.84
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2017		411,498		$	30.71
Exercised		(209,688	)	$	27.86
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2018		201,810		$	33.68
Exercised		(93,682	)	$	31.21
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2019		108,128		$	35.82	$	6,033,654
Vested plus expected to vest at December 31, 2019		108,128		$	35.82	$	6,033,654
Exercisable at December 31, 2019		108,128		$	35.82	$	6,033,654

Schedule of Stock Options Outstanding by Exercise Price Range

Information regarding stock options outstanding as of December 31, 2019 is summarized below:

	OPTIONS OUTSTANDING						OPTIONS EXERCISABLE
Range of Exercise Prices	Number Outstanding As of December 31, 2019		Weighted Average Remaining Contractual Term		Weighted Average Exercise Price		Number Exercisable As of December 31, 2019		Weighted Average Exercise Price
$21.77 to $25.00		1,915		1.3	$	21.77		1,915	$	21.77
$25.01 to $27.00		6,332		2.2	$	25.66		6,332	$	25.66
$27.01 to $40.00		28,886		3.2	$	27.03		28,886	$	27.03
$40.01 to $41.00		70,995		4.2	$	40.88		70,995	$	40.68
$21.77 to $41.00		108,128		3.8	$	35.82		108,128	$	35.82

Summary of Non-employee Director Awards

A summary of the Company’s non-employee director awards of unregistered shares granted by fiscal year is presented below.

For the Year ended December 31,	Number of shares Granted		Weighted- Average Grant Date Fair Value
2017		13,861	$	48.41
2018		7,985	$	60.36

Beginning on July 2, 2018, the Company granted awards of registered shares to its non-employee directors on an annual basis under the Omnibus Plan.  A summary of the non-employee director awards is presented below:

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2018		—		$	—
Granted		11,606		$	72.35
Vested		(5,395	)	$	72.35
Cancelled		(1,243	)	$	72.35
Non-vested RSUs at December 31, 2018		4,968		$	72.35
Granted		9,732		$	73.94
Vested		(9,840	)	$	73.14
Cancelled		—		$	—
Non-vested RSUs at December 31, 2019		4,860		$	73.94	$	445,273
RSUs expected to vest in the future		4,860		$	73.94	$	445,273

Summary of Performance Shares Activity

A summary of the Company’s PSAs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested PSAs at January 1, 2017		129,974		$	40.57
Granted		60,929		$	38.81
Vested		—		$	—
Cancelled		(3,881	)	$	42.83
Non-vested PSAs at December 31, 2017		187,022		$	39.95
Granted		45,136		$	65.05
Vested		(30,576	)	$	44.21
Cancelled		(32,096	)	$	43.72
Non-vested PSAs at December 31, 2018		169,486		$	45.15
Granted		85,928		$	62.07
Vested		(107,000	)	$	37.21
Cancelled		—		$	—
Non-vested PSAs at December 31, 2019		148,414		$	60.67	$	13,597,691
PSAs expected to vest in the future		89,525		$	73.83	$	8,202,281

Schedule of Fair Value Assumptions using Monte Carlo Simulation Model for Awards Granted

The fair value assumptions using the Monte Carlo simulation model for awards granted in 2019, 2018, and 2017 were:

	2019			2018			2017
Dividend Yield		0.7	%		0.9	%		0.0	%
Historical Volatility		29.3	%		31.9	%		31.3	%
Risk-Free Rate of Returns		2.4	%		2.4	%		1.5	%

Restricted Stock Units (RSUs)

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Restricted Stock Unit Activity

A summary of the Company’s RSUs is presented below. 

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2017		507,998		$	36.12
Granted		194,227		$	41.41
Vested		(179,974	)	$	35.19
Cancelled		(58,664	)	$	36.04
Non-vested RSUs at December 31, 2017		463,587		$	38.71
Granted		235,480		$	65.37
Vested		(169,279	)	$	38.66
Cancelled		(55,548	)	$	47.50
Non-vested RSUs at December 31, 2018		474,240		$	50.93
Granted		159,831		$	77.74
Vested		(164,913	)	$	43.82
Cancelled		(19,183	)	$	56.18
Non-vested RSUs at December 31, 2019		449,975		$	62.48	$	41,226,710
RSUs expected to vest in the future		419,706		$	61.77	$	38,453,464

Cash Settled RSUs

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Restricted Stock Unit Activity

CSRSUs generally have a vesting term of three to four years. A summary of the Company’s CSRSUs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested CSRSUs at January 1, 2017		463,022		$	35.96
Granted		174,419		$	42.06
Vested		(161,576	)	$	40.78
Cancelled		(83,949	)	$	36.43
Non-vested CSRSUs at December 31, 2017		391,916		$	38.80
Granted		147,103		$	60.84
Vested		(147,759	)	$	38.71
Cancelled		(53,854	)	$	43.07
Non-vested CSRSUs at December 31, 2018		337,406		$	47.73
Granted		103,606		$	77.03
Vested		(123,395	)	$	44.61
Cancelled		(21,496	)	$	53.92
Non-vested CSRSUs at December 31, 2019		296,121		$	58.83	$	27,130,606
CSRSUs expected to vest in the future		276,247		$	57.98	$	25,309,750