Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

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

Schedule of restricted stock units activity

The following table summarizes restricted stock unit grants by grantee type during the years ended December 31, 2018, 2017 and 2016:

Year Ended December 31	Grantee Type	Number of Restricted Stock Units Granted	Vesting Period	Grant Date Fair Value
2018	Director group	373,438	1-3 years	$	5,975,008
2018	Employee group	1,263,751	1-4 years	$	22,195,706
2017	Director group	18,348	2-3 years	$	198,892
2017	Employee group	141,288	5 years	$	1,897,498
2016	Director group	18,348	2-3 years	$	198,892

The following table provides a summary of restricted stock awards activity under the 2010 and 2017 Plans as of December 31, 2018:

Year Ended December 31, 2018
Restricted Stock	Number of Time-Based Restricted Stock Units		Aggregate Intrinsic Value (in millions)		Number of Performance-Based Restricted Stock Units	Aggregate Intrinsic Value (in millions)		Number of Market Performance-Based Restricted Stock Units		Aggregate Intrinsic Value (in millions)
Non-vested as of December 31, 2017	34,633		N/A		71,428	N/A		—		N/A
Granted	1,033,189				—			604,000
Vested (1)	(19,566	)			—			—
Forfeited	(20,000	)			—			(16,500	)
Non-vested as of December 31, 2018	1,028,256		$	26.3	71,428	$	1.8	587,500		$	15.0

The weighted average grant-date fair value of restricted stock units granted during years 2018, 2017, and 2016 was $17.21, $13.13 and $10.84 per unit, respectively. As of December 31, 2018 the weighted average grant date fair value of vested restricted stock units was $11.27, for forfeited restricted stock units was $14.83, and non-vested restricted stock units was $17.06 per unit.

(1) For certain vested restricted stock units, common shares shall not be issued until the first to occur of: (1) termination of service; (2) change in control; (3) death; or (4) disability, as defined in the 2010 Plan. For certain vested restricted stock units, common shares shall not be issued until the first to occur of: (1) change in control or (2) set cliff vesting dates, as defined in the 2010 Plan. Holders of these certain vested restricted stock units are entitled to receive dividends, but are not entitled to vote the shares until common shares are issued. The amount of vested restricted stock units was 613,605 as of December 31, 2018 and had a related aggregate intrinsic value of $15.7 million at $25.54 per unit.

Schedule of market performance-based restricted stock units thresholds

Awards will vest based on the Company’s TSR relative to the percentage appreciation (rounded to the nearest tenth of a percent), in the value per share of stock during the performance period, over a three-year market performance period, commencing on January 18, 2018 and ending on December 31, 2020 (or, if earlier, ending on the date on which a change in control of the Company occurs), subject to continued services. In the event that the TSR upon completion of the market performance period is achieved at the “minimum,” “target” or “maximum” level as set forth below, the awards will become vested as to the market condition with respect to the percentage RSUs, as applicable, set forth below:

Performance Level Thresholds	TSR	Market Performance Percentage
Minimum	8%	50% of Target Award
Target	10%	100% of Target Award
Maximum	12%	150% of Target Award

Schedule of performance-based restricted stock unit valuation assumptions

Assumptions used in the valuations are summarized as follows:

Award Date	Expected Stock Price Volatility	Risk-Free Interest Rate	Dividend Yield
2/26/2018	30%	2.35%	4.70%
4/2/2018	30%	2.34%	4.04%
7/1/2018	30%	2.58%	3.41%
10/1/2018	25%	2.85%	3.01%

The key assumptions used in the valuation of the April 2017 award was as follows:

Award Date	Expected Stock Price Volatility	Risk-Free Interest Rate	Dividend Yield
4/10/2017	30%	1.63%	2%

Schedule of stock option activity

The following table provides a summary of option activity for the year ended December 31, 2018:

	Number of Options		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Terms (Years)	Aggregate Intrinsic Value (in millions)
Outstanding as of December 31, 2017	5,477,617		$	9.72	6.0	N/A
Granted	—		—
Exercised	(2,993,709	)	9.69
Forfeited or expired	(128,121	)	8.84
Outstanding as of December 31, 2018	2,355,787		$	9.81	5.4	$	37.1
Exercisable as of December 31, 2018	1,167,789		$	9.81	3.8	$	18.4

The following table summarizes stock option grants under the 2010 Plan during the year ended December 31, 2016:

Year Ended December 31	Grantee Type	# of Options Granted	Vesting Period	Weighted- Average Exercise Price	Grant Date Fair Value
2016	Employee group	1,355,000	5 years	$9.81	$	4,674,750

Schedule of stock option valuation

The Company’s calculations of the fair value of stock options granted during the year ended December 31, 2016 were determined based on the Black-Scholes option-pricing model utilizing the following assumptions:

	2016
Weighted-average expected life	6.6 years
Risk-free interest rate	1.6%
Expected volatility	33%
Expected dividend yield	2.0%