ADJUSTED EBITDA

(in thousands)

Three Months Ended

Six Months Ended June 30,

2012

2011

2012

2011

Net income

$        14,091

$        13,409

$        29,847

$        25,656

Adjustments:

Interest (income) expense, net

(1,307)

2,604

(1,360)

7,127

Provision for income taxes

9,341

7,579

19,338

15,003

Depreciation and amortization

17,756

17,492

35,495

34,218

Transaction costs

2,376

-

2,376

-

Non-cash stock-based compensation expense

2,435

2,892

5,176

5,737

Adjusted EBITDA

$        44,692

$        43,976

$        90,872

$        87,741

Adjusted EBITDA is a non-GAAP financial measure that represents net income before depreciation and amortization expenses, net interest income or expense, provision for income taxes, non-cash stock-based compensation expense and other items including transaction related costs.  We believe that Adjusted EBITDA provides useful information to investors because it is an indicator of the strength and performance of our ongoing operations.  However, Adjusted EBITDA is not a recognized term under financial performance under GAAP, and our calculation of Adjusted EBITDA may not be comparable to the calculation of similarly titled measures of other companies.