Assets Held for Sale or Contribution and Discontinued Operations - Summary of Assets Held for Sale and Contribution (Detail) ft² in Thousands, $ in Thousands	Dec. 31, 2015 USD ($) ft² Property	Dec. 31, 2014 USD ($) ft² Property
Long Lived Assets Held For Sale [Line Items]
Total assets held for sale or contribution	$ 378,423	$ 43,934
Total liabilities associated with assets held for sale or contribution – included in Other Liabilities	$ 6,874	$ 0
Disposal Group Heldforsale Not Discontinued Operations
Long Lived Assets Held For Sale [Line Items]
Number of buildings \| Property	17	7
Square feet \| ft²	5,065	457

Amount classified as liabilities attributable to disposal group held for sale or disposed of.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2941-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e1107-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721533-107759

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721673-107760

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