Stock-Based Compensation
 3 Months Ended
Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Stock-Based Compensation
Stock-Based Compensation
At March 31, 2015, we had a stock-based employee compensation program, for which we had reserved a total of 4,943,170 common shares for issuance. Under our 2012 Equity Participation Plan (Equity Plan), which was approved by our stockholders on June 7, 2012, a total of 1,422,130 shares of our common stock were available for issuance and no new awards will be issued under any previous equity participation plans. As of March 31, 2015, there were 552,234 shares of our common stock available for future grants under our Equity Plan, which included the canceled and forfeited shares issued under previous equity participation plans.
All option awards previously granted were issued with exercise prices equal to the closing price of our common stock on the NASDAQ Global Select Market on the dates of the grant. The options under the Equity Plan generally vest over a four-year period from date of grant, and options terminate on the 10th anniversary of the agreement date for all grants issued before January 1, 2013 and on the 7th anniversary of the agreement date for all grants issued after December 31, 2012. Restricted stock awards generally vest over a four-year period from date of the award. Performance stock units granted prior to 2015 generally vest over two to three years from date of the award based on the expected level of achievement of certain operational goals that will be obtained and adjusted as appropriate to reflect actual shares issued. Performance stock units granted in 2015 generally vest over three to four years from date of the award based on the expected level of achievement of certain market conditions that will be obtained and adjusted as appropriate to reflect actual shares issued.
Stock-based compensation expense is recognized over the period when the options, restricted stock awards, performance stock awards and our employee stock purchase plan shares vest, which is included in total general and administrative expenses as follows (in thousands):
 
Three Months Ended March 31,
 
2015
 
2014
Total stock-based compensation expense
$
1,904

 
$
1,965

Tax benefit from stock-based compensation expense
(724
)
 
(753
)
Total stock-based compensation expense, net of tax
$
1,180

 
$
1,212


As of March 31, 2015, total unrecognized compensation costs related to non-vested stock-based compensation arrangements granted under our Equity Plan and previous equity participation plans and the weighted-average period of years expected to recognize those costs are as follows (dollars in thousands):
 
Total Unrecognized
Compensation
Cost
 
Weighted -average
Remaining Recognition
Period
 
 
 
(Years)
Stock option
$
1,165

 
1.59
Restricted/Performance stock
$
12,764

 
2.02

The grant date fair value of each restricted stock award or performance stock units with operational goals is based on the closing stock price on the grant date of the award as reported by NASDAQ Global Select Market. The grant date fair value of each performance stock units with market conditions is determined using a Monte-Carlo simulation model. Key assumptions for Monte-Carlo simulation model are the risk-free interest rate, expected volatility and correlation coefficient.
The following table summarizes the stock option activities in our Equity Plan during the three months ended March 31, 2015:
 
Shares
 
Weighted-
Average
Exercise
Price
 
Weighted-
Average
Remaining
Contractual
Term
 
Aggregate
Intrinsic
Value
 
Weighted-
Average 
Fair
Value
 
 
 
 
 
(Years)
 
(in 000s)
 
 
Options outstanding as of December 31, 2014
1,234,530

 
$
31.10

 
 
 
 
 
$
12.75

Changes during period:
 
 
 
 
 
 
 
 
 
Granted
—

 
—

 
 
 
 
 
—

Exercised
(17,062
)
 
26.40

 
 
 
 
 
10.94

Cancelled
(1,245
)
 
35.23

 
 
 
 
 
14.46

Options outstanding as of March 31, 2015
1,216,223

 
$
31.16

 
4.94
 
$
19,178

 
$
12.77

Options exercisable as of March 31, 2015
1,135,076

 
$
30.45

 
4.83
 
$
18,641

 
$
12.59


The following table summarizes the restricted stock award and performance stock award activities in our Equity Plan during the three months ended March 31, 2015:
 
Shares
 
Weighted-
Average
Remaining
Contractual
Term
 
Aggregate
Intrinsic
Value
 
Weighted-
Average
Fair
Value
 
 
 
(Years)
 
(in 000s)
 
 
Restricted/performance stock awards outstanding as of December 31, 2014
265,219

 
 
 
 
 
$
45.69

Changes during period:
 
 
 
 
 
 
 
Granted
183,214

 
 
 
 
 
44.01

Vested
(105,194
)
 
 
 
 
 
41.89

Forfeited
(1,136
)
 
 
 
 
 
47.69

Restricted/performance stock awards outstanding as of March 31, 2015
342,103

 
2.02
 
$
15,956

 
$
46.86