Employee Benefit Plans - Schedule of Amounts in AOCI on Consolidated Statement of Financial Condition Expected to be Recognized (Detail) - Pension Plans [Member] $ in Thousands	12 Months Ended
Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 30
Net actuarial loss (gain)	$ 5,291

Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) 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.

No definition available.

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