|
Postretirement Benefit Plans - Summary of PME Multi-Employer Plan (Parenthetical) (Detail) (PME Multi-Employer Plan [Member])
|
12 Months Ended |
|---|---|
|
Dec. 31, 2012
|
|
|
PME Multi-Employer Plan [Member]
|
|
| Multiemployer Plans [Line Items] | |
| Percentage of total contribution | 5.00% |