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Stockholders' Equity (Stock Repurchase Program) (Details) - USD ($) $ / shares in Units, $ in Thousands | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2021 | Nov. 02, 2020 | Dec. 31, 2013
Share-based Payment Arrangement [Abstract] |  |  |
Stock repurchase program, authorized amount | $ 117,700 | $ 250,000 |
Number of shares authorized to be repurchased under the Repurchase Program (in shares) |  |  | 10,000,000
Number of remaining shares authorized to be repurchased under the Repurchase Program (in shares) |  |  | 6,600,000
Shares repurchased and retired (in shares) | 11,606,229 |  |
Average cost per share (usd per share) | $ 4.14 |  |
Cost for shares repurchased | $ 48,100 |  |
Payments for fees and commissions paid to the sales agent | $ 116 |  |

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