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Stock-Based Compensation Plans - Summary of Nonvested LTIP Performance Shares (Details) - LTIP Performance Shares
12 Months Ended
Dec. 31, 2020
$ / shares
shares
Number of Shares at Expected Attainment  
Nonvested, beginning balance (in shares) | shares 669,469
Vested (in shares) | shares (668,240)
Forfeited (in shares) | shares (5,368)
Change in expected attainment (in shares) | shares 4,139
Nonvested, ending balance (in shares) | shares 0
Weighted Average Grant Date Fair Value  
Nonvested, beginning balance (in dollars per share) | $ / shares $ 20.12
Vested (in dollars per share) | $ / shares 20.12
Forfeited (in dollars per share) | $ / shares 20.12
Change in expected attainment (in dollars per share) | $ / shares 20.12
Nonvested, ending balance (in dollars per share) | $ / shares $ 0