Retirement Plans - Allocation of Plan Assets, Pension Plan (Details) - Pension Plan - USD ($)
$ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
$ 235.8
|
$ 0.0
|
$ 3,219.9
|
| Fair Value, Inputs, Level 1 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
71.7
|
|
|
| Fair Value, Inputs, Level 2 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
96.2
|
|
|
| Cash and Cash Equivalents |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
6.4
|
|
|
| Cash and Cash Equivalents | Fair Value, Inputs, Level 1 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
4.1
|
|
|
| Cash and Cash Equivalents | Fair Value, Inputs, Level 2 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
2.3
|
|
|
| Equity |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
67.6
|
|
|
| Equity | Fair Value, Inputs, Level 1 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
67.6
|
|
|
| Equity | Fair Value, Inputs, Level 2 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
0.0
|
|
|
| Fixed Income |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
93.9
|
|
|
| Fixed Income | Fair Value, Inputs, Level 1 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
0.0
|
|
|
| Fixed Income | Fair Value, Inputs, Level 2 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
93.9
|
|
|
| Equity Funds Measured at NAV |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
67.9
|
|
|
| Equity Funds Measured at NAV | Fair Value, Inputs, Level 1 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
0.0
|
|
|
| Equity Funds Measured at NAV | Fair Value, Inputs, Level 2 |
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
| Fair value of the company's benefit plan assets |
$ 0.0
|
|
|