Income Taxes - Summary of Deferred Tax Assets and Liabilities (Parenthetical)(Detail) - TRS [Member] $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Income Tax Expense Benefit [Line Items]
Net operating loss carryforwards	$ 37.8
Expiry of net operating loss carryforwards	2022 through 2035

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

No definition available.

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant