Debt and Interest Expense - Summary of Total Long-term Debt (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2019
5.625% Fixed Rate Senior Notes due 2026
Debt Instrument [Line Items]
Debt instrument interest rate	5.625%
Debt instrument due year	2026
5.125% Fixed Rate Senior Notes due 2028
Debt Instrument [Line Items]
Debt instrument interest rate	5.125%
Debt instrument due year	2028

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant