|**Earnings Per Share (Tables)**                                                                                       | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
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|**Earnings Per Share [Abstract]**                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Schedule of Earnings Per Share Reconciliation                                                                         | The following table presents our weighted-average basic and diluted shares outstanding:Three Months Ended September 30,Nine Months Ended September 30,2018201720182017(in thousands)Weighted-average common shares outstanding - basic66,07365,86566,03265,825Weighted-average common shares and equivalents outstanding - diluted66,07365,86566,03265,825                                                                                                                                                     
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|                                                                                                                      | Three Months Ended September 30,                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                                                                                      | 2018                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|                                                                                                                      | (in thousands)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Weighted-average common shares outstanding - basic                                                                    | 66,073                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Weighted-average common shares and equivalents outstanding - diluted                                                  | 66,073                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share                                   | The following table presents the weighted-average common share equivalents excluded from the calculation of diluted earnings per share due to their anti-dilutive effect:Three Months Ended September 30,Nine Months Ended September 30,2018201720182017(in thousands)Weighted-average common share equivalents excluded from diluted earnings per share due to their anti-dilutive effect:RSU and PSU719588655585Other equity-based awards3144831982Total anti-dilutive common share equivalents1,033636974667
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|                                                                                                                      | Three Months Ended September 30,                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                                                                                      | 2018                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|                                                                                                                      | (in thousands)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Weighted-average common share equivalents excluded from diluted earnings per share due to their anti-dilutive effect: |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|RSU and PSU                                                                                                           | 719                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Other equity-based awards                                                                                             | 314                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Total anti-dilutive common share equivalents                                                                          | 1,033                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
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