Employee Benefit Plans - Estimated Amounts Amortized from Accumulated Other Comprehensive Loss (Detail) - Pension Benefits [Member] $ in Thousands	12 Months Ended
Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	$ 37,870
Prior service credit	(349)
Total	$ 37,521

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

No definition available.

Name:	us-gaap_DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration