Equity - Noncontrolling Interests (Detail) - Non-controlling Interests - shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Equity [Line Items]
Preferred stock, shares outstanding (in shares)	125	125
Preferred stock, dividend rate (as a percent)	12.50%	12.50%
Common Class B
Equity [Line Items]
Total common equity (as a percent)	42.00%	43.00%

Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_PreferredStockSharesOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant