Non-Controlling Interests, Preferred Shares, Common Shares and Common Shares in Treasury - Preferred Shares Outstanding (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Preferred Shares Outstanding [Line Items]
Cumulative redeemable preferred shares	$ 350,000	$ 350,000
Class J cumulative redeemable preferred shares [Member]
Preferred Shares Outstanding [Line Items]
Cumulative redeemable preferred shares	200,000	200,000
Class K cumulative redeemable preferred shares [Member]
Preferred Shares Outstanding [Line Items]
Cumulative redeemable preferred shares	$ 150,000	$ 150,000

Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29
-Article 5

Name:	us-gaap_PreferredStockValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant