Business Segments - Segment Reporting, Reconciliation of Revenues, Operating Income and Assets (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenues	$ 619,922	$ 602,874	$ 766,183	$ 629,155	$ 620,115	$ 704,565	$ 602,155	$ 606,300	$ 2,618,134	$ 2,533,135	$ 2,197,074
Consolidated net earnings	158,417	$ 175,491	$ 275,272	$ 161,886	164,208	$ 232,624	$ 142,348	$ 129,198	771,066	668,378	380,172
General and administrative expenses									231,059	222,067	217,227
Depreciation and amortization expenses									879,140	930,985	880,373
Earnings from unconsolidated entities, net									248,567	206,307	159,262
Interest expense									(274,486)	(303,146)	(301,363)
Interest and other income, net									13,731	8,101	25,484
Gains on dispositions of investments in real estate and revaluation of equity investments upon acquisition of a controlling interest, net									1,182,965	757,398	758,887
Foreign currency and derivative gains (losses), net									(57,896)	7,582	12,466
Gains (losses) on early extinguishment of debt, net									(68,379)	2,484	(86,303)
Earnings before income taxes									1,815,568	1,347,104	948,605
Total assets	29,481,075				30,249,932				29,481,075	30,249,932
Investments in and advances to unconsolidated entities	5,496,450				4,230,429				5,496,450	4,230,429
Assets held for sale or contribution	342,060				322,139				342,060	322,139
Notes receivable backed by real estate	34,260				32,100				34,260	32,100	235,050
Cash and cash equivalents	447,046				807,316				447,046	807,316	264,080	$ 350,692
Other assets	1,381,963				1,496,990				1,381,963	1,496,990
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues									2,618,134	2,533,135	2,197,074
Consolidated net earnings									1,881,265	1,821,430	1,477,772
Total assets	22,960,741				24,614,975				22,960,741	24,614,975
Operating Segments [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									2,244,245	2,229,573	1,979,245
Consolidated net earnings									1,662,517	1,646,374	1,368,365
Total assets	22,918,099				24,547,949				22,918,099	24,547,949
Operating Segments [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues									373,889	303,562	217,829
Consolidated net earnings									218,748	175,056	109,407
Total assets	42,642				67,026				42,642	67,026
Operating Segments [Member] | U.S. [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									2,025,184	2,040,308	1,801,858
Consolidated net earnings									1,519,164	1,520,571	1,256,188
Total assets	19,058,610				21,286,422				19,058,610	21,286,422
Operating Segments [Member] | U.S. [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues									176,720	39,360	39,396
Consolidated net earnings									106,471	(1,622)	(1,925)
Total assets	16,818				18,090				16,818	18,090
Operating Segments [Member] | Other Americas [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									84,789	58,519	57,316
Consolidated net earnings									58,842	38,114	38,061
Total assets	1,767,385				978,476				1,767,385	978,476
Operating Segments [Member] | Other Americas [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues									28,494	22,799	22,507
Consolidated net earnings									16,811	12,777	13,496
Operating Segments [Member] | Europe [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									73,708	75,602	69,576
Consolidated net earnings									51,277	54,406	39,721
Total assets	1,008,340				1,346,589				1,008,340	1,346,589
Operating Segments [Member] | Europe [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues									106,862	186,652	112,744
Consolidated net earnings									68,127	144,132	86,215
Total assets	25,280				47,635				25,280	47,635
Operating Segments [Member] | Asia [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									60,564	55,144	50,495
Consolidated net earnings									33,234	33,283	34,395
Total assets	1,083,764				936,462				1,083,764	936,462
Operating Segments [Member] | Asia [Member] | Strategic Capital [Member]
Segment Reporting Information [Line Items]
Total revenues									61,813	54,751	43,182
Consolidated net earnings									27,339	19,769	11,621
Total assets	544				1,301				544	1,301
Reconciling Items [Member]
Segment Reporting Information [Line Items]
Consolidated net earnings									771,066	668,378	380,172
General and administrative expenses									231,059	222,067	217,227
Depreciation and amortization expenses									879,140	930,985	880,373
Earnings from unconsolidated entities, net									248,567	206,307	159,262
Interest expense									(274,486)	(303,146)	(301,363)
Interest and other income, net									13,731	8,101	25,484
Gains on dispositions of investments in real estate and revaluation of equity investments upon acquisition of a controlling interest, net									1,182,965	757,398	758,887
Foreign currency and derivative gains (losses), net									(57,896)	7,582	12,466
Gains (losses) on early extinguishment of debt, net									(68,379)	2,484	$ (86,303)
Total assets	6,520,334				5,634,957				6,520,334	5,634,957
Investments in and advances to unconsolidated entities	5,496,450				4,230,429				5,496,450	4,230,429
Assets held for sale or contribution	342,060				322,139				342,060	322,139
Notes receivable backed by real estate	34,260				32,100				34,260	32,100
Cash and cash equivalents	447,046				807,316				447,046	807,316
Other assets	$ 200,518				$ 242,973				$ 200,518	$ 242,973