Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation Plans and Awards - MSUs Narrative (Details)

v3.8.0.1
Stock-based Compensation Plans and Awards - MSUs Narrative (Details)
$ in Thousands
 1 Months Ended 3 Months Ended 9 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Mar. 31, 2015
performance_period
Sep. 30, 2017
USD ($)
shares
Sep. 30, 2016
USD ($)
shares
Sep. 30, 2017
USD ($)
shares
Sep. 30, 2016
USD ($)
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock-based compensation expense       $ 30,101 $ 32,754 $ 98,327 $ 103,841
Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Requisite service period           4 years  
Market Stock Units (MSUs)              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of performance periods | performance_period     3        
Requisite service period     3 years        
TSR prior to beginning of performance period     90 days        
TSR at end of performance period     90 days        
Performance multiplier, percentage point decrease     3.00%        
Grants in period (in shares) | shares       0 0 0 0
Stock-based compensation expense       $ 100 $ 200 $ 300 $ 600
Market Stock Units (MSUs) | One-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Vesting percent   22.00% 33.33%        
TSR decline (percent)   26.00%          
Market Stock Units (MSUs) | Two-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Vesting percent 0.00%   33.33%        
TSR decline (percent) 48.00%            
Market Stock Units (MSUs) | Three-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance multiplier, percentage point increase     2.00%        
Market Stock Units (MSUs) | Maximum | One-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance multiplier     100.00%        
Market Stock Units (MSUs) | Maximum | Two-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance multiplier     100.00%        
Market Stock Units (MSUs) | Maximum | Three-Year Performance Period              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance multiplier     200.00%