Earnings (Loss) Per Share - Securities Excluded from Computations of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Restricted Stock Units [Member]
Employee and director:
Securities excluded from computation of diluted earning per share	1,027	623
Stock Appreciation Rights [Member]
Employee and director:
Securities excluded from computation of diluted earning per share	1,022	1,237

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration