ADJUSTED EBITDA

(in thousands)

Three Months Ended March 31,

2012

2011

Net income

$ 15,756

$ 12,247

Adjustments:

Interest (income) expense, net

(53)

4,523

Provision for income taxes

9,997

7,424

Depreciation and amortization

17,739

16,726

Non-cash stock-based compensation expense

2,741

2,845

Adjusted EBITDA

$ 46,180

$ 43,765