Business Segments - Segment Reporting, Reconciliation of Revenues, Operating Income and Assets (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total revenues	$ 580,622		$ 415,151	$ 1,553,873		$ 1,309,922
General and administrative expenses	(59,375)		(58,203)	(172,690)		(181,781)
Depreciation and amortization	(247,471)		(149,202)	(607,467)		(471,059)
Earnings from unconsolidated entities, net	33,557		28,514	106,383		79,411
Interest expense	(81,035)		(69,086)	(218,698)		(234,793)
Interest and other income, net	6,237		550	19,133		19,716
Gains on acquisitions and dispositions of investments in real estate, net	268,791		151,057	655,288		337,695
Foreign currency and derivative gains (losses) and related amortization, net	(9,428)		20,792	(374)		2,738
Losses on early extinguishment of debt, net			(86,076)	(16,525)		(163,361)
Consolidated net earnings	103,392		78,112	274,621		244,852
Consolidated net earnings (loss)	218,122		45,751	545,207		41,406
Investments in and advances to unconsolidated entities	4,841,225			4,841,225			$ 4,824,724
Assets held for sale	369,382	[1]		369,382	[1]		43,934
Cash and cash equivalents	310,433		311,879	310,433		311,879	350,692	$ 491,129
Earnings before income taxes	321,514		123,863	819,828		286,258
Total assets	31,419,354			31,419,354			25,818,223
Note receivable backed by real estate	197,500			197,500
Other assets	1,587,901			1,587,901			1,199,509
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	580,622		415,151	1,553,873		1,309,922
Consolidated net earnings	410,238		285,517	1,054,778		897,692
Total assets	25,421,687			25,421,687			20,258,013
Operating Segments [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	536,446		361,081	1,420,626		1,134,208
Consolidated net earnings	387,776		253,889	983,721		796,420
Total assets	25,348,748			25,348,748			20,180,083
Operating Segments [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues	44,176		54,070	133,247		175,714
Consolidated net earnings	22,462		31,628	71,057		101,272
Total assets	72,939			72,939			77,930
Operating Segments [Member] | Americas [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	503,487		324,877	1,326,446		1,025,349
Consolidated net earnings	365,723		230,515	923,118		727,245
Total assets	22,986,722			22,986,722			17,432,909
Operating Segments [Member] | Americas [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues	14,692		18,567	46,734		80,457
Consolidated net earnings	2,966		6,451	15,091		38,599
Total assets	19,681			19,681			20,635
Operating Segments [Member] | Europe [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	17,591		20,422	53,041		57,083
Consolidated net earnings	11,092		12,072	32,173		31,706
Total assets	1,286,275			1,286,275			1,820,529
Operating Segments [Member] | Europe [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues	20,652		24,713	60,046		65,866
Consolidated net earnings	14,285		17,791	40,576		43,600
Total assets	51,085			51,085			54,577
Operating Segments [Member] | Asia [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	15,368		15,782	41,139		51,776
Consolidated net earnings	10,961		11,302	28,430		37,469
Total assets	1,075,751			1,075,751			926,645
Operating Segments [Member] | Asia [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues	8,832		10,790	26,467		29,391
Consolidated net earnings	5,211		7,386	15,390		19,073
Total assets	2,173			2,173			2,718
Reconciling Items [Member]
Segment Reporting Information [Line Items]
General and administrative expenses	(59,375)		(58,203)	(172,690)		(181,781)
Depreciation and amortization	(247,471)		(149,202)	(607,467)		(471,059)
Earnings from unconsolidated entities, net	33,557		28,514	106,383		79,411
Interest expense	(81,035)		(69,086)	(218,698)		(234,793)
Interest and other income, net	6,237		550	19,133		19,716
Gains on acquisitions and dispositions of investments in real estate, net	268,791		151,057	655,288		337,695
Foreign currency and derivative gains (losses) and related amortization, net	(9,428)		20,792	(374)		2,738
Losses on early extinguishment of debt, net			(86,076)	(16,525)		(163,361)
Consolidated net earnings (loss)	(88,724)		$ (161,654)	(234,950)		$ (611,434)
Investments in and advances to unconsolidated entities	4,841,225			4,841,225			4,824,724
Assets held for sale	369,382			369,382			43,934
Cash and cash equivalents	310,433			310,433			350,692
Total assets	5,997,667			5,997,667			5,560,210
Note receivable backed by real estate	197,500			197,500			0
Other assets	$ 279,127			$ 279,127			$ 340,860

[1] Includes two parcels of land held for sale at September 30, 2015