Consolidated Statements of Stockholder's Equity Consolidated Statements of Stockholder's Equity - USD ($) shares in Thousands, $ in Millions | Total | Common Stock | Additional Paid-In Capital | Retained Earnings | Accumulated Other Comprehensive Loss |
Beginning balance (in shares) at Dec. 31, 2018 | | 16,482 | | | |
Beginning balance at Dec. 31, 2018 | $ 426.4 | $ 0 | $ 6.4 | $ 487.3 | $ (67.3) |
Net income | 3.8 | | | 3.8 | |
Performance share, restricted stock unit, and stock option awards (in shares) | | 33 | | | |
APIC, Share-based Payment Arrangement, Increase for Cost Recognition | 1.2 | | 1.2 | | |
Stock-based compensation expense | (0.4) | | (0.4) | | |
Pension and other postretirement employee benefit plans, net of tax | 1.2 | | | | 1.2 |
Beginning balance (in shares) at Mar. 31, 2019 | | 16,515 | | | |
Beginning balance at Mar. 31, 2019 | 432.2 | $ 0 | 7.2 | 491.1 | (66.1) |
Pension and OPEB, Tax | 0.5 | | | | |
Beginning balance (in shares) at Dec. 31, 2018 | | 16,482 | | | |
Beginning balance at Dec. 31, 2018 | 426.4 | $ 0 | 6.4 | 487.3 | (67.3) |
Net income | 3.4 | | | | |
Beginning balance (in shares) at Jun. 30, 2019 | | 16,515 | | | |
Beginning balance at Jun. 30, 2019 | 434.3 | $ 0 | 8.4 | 490.7 | (64.8) |
Beginning balance (in shares) at Mar. 31, 2019 | | 16,515 | | | |
Beginning balance at Mar. 31, 2019 | 432.2 | $ 0 | 7.2 | 491.1 | (66.1) |
Net income | (0.4) | | | (0.4) | |
APIC, Share-based Payment Arrangement, Increase for Cost Recognition | 1.2 | | 1.2 | | |
Pension and other postretirement employee benefit plans, net of tax | 1.3 | | | | 1.3 |
Beginning balance (in shares) at Jun. 30, 2019 | | 16,515 | | | |
Beginning balance at Jun. 30, 2019 | 434.3 | $ 0 | 8.4 | 490.7 | (64.8) |
Pension and OPEB, Tax | 0.5 | | | | |
Beginning balance (in shares) at Dec. 31, 2019 | | 16,515 | | | |
Beginning balance at Dec. 31, 2019 | 432 | $ 0 | 9.8 | 481.7 | (59.5) |
Net income | 10.3 | | | 10.3 | |
Performance share, restricted stock unit, and stock option awards (in shares) | | 54 | | | |
APIC, Share-based Payment Arrangement, Increase for Cost Recognition | 1.3 | | 1.3 | | |
Stock-based compensation expense | (0.7) | | (0.7) | | |
Pension and other postretirement employee benefit plans, net of tax | 1.8 | | | | 1.8 |
Beginning balance (in shares) at Mar. 31, 2020 | | 16,569 | | | |
Beginning balance at Mar. 31, 2020 | 444.8 | $ 0 | 10.4 | 492.1 | (57.7) |
Pension and OPEB, Tax | 0.6 | | | | |
Beginning balance (in shares) at Dec. 31, 2019 | | 16,515 | | | |
Beginning balance at Dec. 31, 2019 | 432 | $ 0 | 9.8 | 481.7 | (59.5) |
Net income | 33.1 | | | | |
Beginning balance (in shares) at Jun. 30, 2020 | | 16,571 | | | |
Beginning balance at Jun. 30, 2020 | 470.8 | $ 0 | 11.8 | 514.8 | (55.8) |
Beginning balance (in shares) at Mar. 31, 2020 | | 16,569 | | | |
Beginning balance at Mar. 31, 2020 | 444.8 | $ 0 | 10.4 | 492.1 | (57.7) |
Net income | 22.8 | | | 22.8 | |
Performance share, restricted stock unit, and stock option awards (in shares) | | 2 | | | |
APIC, Share-based Payment Arrangement, Increase for Cost Recognition | 1.4 | | 1.4 | | |
Stock-based compensation expense | 0 | | 0 | | |
Pension and other postretirement employee benefit plans, net of tax | 1.8 | | | | 1.8 |
Beginning balance (in shares) at Jun. 30, 2020 | | 16,571 | | | |
Beginning balance at Jun. 30, 2020 | 470.8 | $ 0 | $ 11.8 | $ 514.8 | $ (55.8) |
Pension and OPEB, Tax | $ 0.6 | | | | |