Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Option Activity

Stock option activity from January 1, 2019 to March 31, 2019 follows:

			Weighted
			Average
	Underlying		Exercise Price
	Shares		Per Share
Outstanding at January 1, 2019		5,501,150	$	19.63
Exercised		—	$	-
Expired		—	$	-
Outstanding at March 31, 2019		5,501,150	$	19.63
Exercisable at March 31, 2019		5,432,679	$	19.64

Restricted Stock Activity

Restricted stock activity from January 1, 2019 to March 31, 2019 follows:

				Weighted
				Average Grant
				Date Fair Value
	Shares			Per Share
Non-vested restricted stock outstanding at January 1, 2019		436,224		$	21.41
Vested		(64,494	)	$	20.61
Forfeited		(1,033	)	$	21.71
Non-vested restricted stock outstanding at March 31, 2019		370,697		$	21.55

Restricted Stock Unit Activity

Restricted stock unit activity from January 1, 2019 to March 31, 2019 follows:

						Weighted
						Average Grant
	Time			Performance		Date Fair Value
	Based			Based		Per Share
Non-vested restricted stock units outstanding at January 1, 2019		2,602,608			435,315	$	18.95
Granted		101,448			—	$	10.35
Vested		(38,615	)		—	$	22.95
Forfeited		(46,738	)		—	$	19.23
Non-vested restricted stock units outstanding at March 31, 2019		2,618,703			435,315	$	18.61

Performance Units

The total target number of shares with respect to the Performance Units for the awards granted in 2015-2018 is set forth below:

	2018		2017		2016		2015
	Performance		Performance		Performance		Performance
	Unit Awards		Unit Awards		Unit Awards		Unit Awards
Target number of shares		310,700		186,198		185,000		190,600

Fair Value of Performance Units

The fair value of the Performance Units is set forth below (in thousands):

	2018		2017		2016		2015
	Performance		Performance		Performance		Performance
	Unit Awards		Unit Awards		Unit Awards		Unit Awards
Fair value at date of grant	$	8,004	$	5,780	$	3,854	$	4,052

Compensation Expense Associated with Performance Units

Compensation expense associated with the Performance Units is shown below (in thousands):

	2018		2017		2016		2015
	Performance		Performance		Performance		Performance
	Unit Awards		Unit Awards		Unit Awards		Unit Awards
Three months ended March 31, 2019	$	667	$	482	$	321	NA
Three months ended March 31, 2018	NA		$	482	$	321	$	338