Income Taxes (Details)
$ / shares in Units, $ in Millions, ₩ in Billions |
3 Months Ended |
|
Mar. 31, 2018
USD ($)
$ / shares
|
Mar. 31, 2018
KRW (₩)
|
Mar. 31, 2017
USD ($)
$ / shares
|
| Income tax provision |
$ 7.3
|
|
$ 5.0
|
| Effective income tax rate |
19.00%
|
19.00%
|
13.90%
|
| Effective income tax rate reconciliation, valuation allowance on U.S. deferred tax assets |
$ 4.9
|
|
|
| Income tax expense due to change in estimate related to uncertain tax position and adjustment for ASU 2016-09 |
|
|
$ 1.2
|
| Special income tax concession period |
5 years
|
5 years
|
|
| Decrease in foreign income taxes due to special income tax concession |
$ (0.1)
|
|
$ 0.8
|
| Impact of income tax concession on basic earnings per common share (in dollars per share) | $ / shares |
$ 0
|
|
$ 0.01
|
| Impact of income tax concession on diluted earnings per common share (in dollars per share) | $ / shares |
$ 0
|
|
$ 0.01
|
| Tax Authority, South Korea (SRTO) |
|
|
|
| Income tax assessment notice, amount |
$ 10.6
|
₩ 11.3
|
|
| Without income tax benefit adjustment and valuation allowance |
|
|
|
| Effective income tax rate |
31.70%
|
31.70%
|
10.60%
|