Capital Stock Capital Stock (Details) - USD ($) |
3 Months Ended | |||
|---|---|---|---|---|
Sep. 30, 2018 |
Oct. 04, 2018 |
Dec. 31, 2017 |
May 08, 2017 |
|
| Subsequent Event [Line Items] | ||||
| Shares of common stock authorized (in shares) | 100,000,000 | 100,000,000 | ||
| Shares issued and outstanding (in shares) | 50,600,000 | 50,500,000 | ||
| Maximum shares allowed for issuance (in shares) | 2,000,000 | |||
| Par value (in dollars per share) | $ 10 | |||
| Stock repurchase program amount | $ 200,000,000 | |||
| Stock repurchase program amount used | $ 25,100,000 | |||
| Stock repurchased (in shares) | 336,829 | |||
| Average price per share (in dollars per share) | $ 74.37 | |||
| Stock repurchase program remaining amount | $ 175,000,000 | |||
| Subsequent Event | ||||
| Subsequent Event [Line Items] | ||||
| Dividend declared (in dollars per share) | $ 0.15 |