Segment Information - Schedule of Financial Information of Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Investment in unconsolidated real estate ventures	$ 79,385		$ 79,570
Total assets	7,034,357		7,091,446
Total revenues	263,008	$ 229,403
Operating expenses, including depreciation and amortization	138,805	135,775
Income (loss) from operations	124,203	93,628
Loss on earnout from prior acquisition	0	(1,544)
Interest expense	(35,970)	(31,359)
Non-cash interest expense related to amortization of discount on equity component of exchangeable senior notes	(1,269)	(1,233)
Interest income	1,102	1,714
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213
Equity in earnings of unconsolidated real estate ventures	3,579	2,830
Equity in earnings of unconsolidated real estate ventures - gain on sale of real estate assets and purchase of joint venture partner's interest	0	26,923
Income tax (expense) benefit	(3,124)	(2,765)
Net income (loss)	89,734	89,407
Depreciation and amortization expense	49,432	42,897
Acquisition of real estate assets	(39,136)	(234,820)
Development and redevelopment of real estate assets	(5,246)	(6,543)
Rental Operations [Member]
Segment Reporting Information [Line Items]
Investment in unconsolidated real estate ventures	79,385		79,570
Total assets	6,729,670		6,731,292
Total revenues	231,493	199,488
Operating expenses, including depreciation and amortization	115,357	101,698
Income (loss) from operations	116,136	97,790
Interest expense	(34,821)	(30,565)
Equity in earnings of unconsolidated real estate ventures	3,579	2,830
Income tax (expense) benefit	(463)	(845)
Net income (loss)	84,431	69,210
Depreciation and amortization expense	48,712	40,586
Tenant Reinsurance [Member]
Segment Reporting Information [Line Items]
Total assets	33,611		44,524
Total revenues	22,855	20,555
Operating expenses, including depreciation and amortization	3,920	4,311
Income (loss) from operations	18,935	16,244
Income tax (expense) benefit	(3,263)	(2,663)
Net income (loss)	15,672	13,581
Property Management, Acquisition and Development [Member]
Segment Reporting Information [Line Items]
Total assets	271,076		$ 315,630
Total revenues	8,660	9,360
Operating expenses, including depreciation and amortization	19,528	29,766
Income (loss) from operations	(10,868)	(20,406)
Loss on earnout from prior acquisition	0	(1,544)
Interest expense	(1,149)	(794)
Non-cash interest expense related to amortization of discount on equity component of exchangeable senior notes	(1,269)	(1,233)
Interest income	1,102	1,714
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213
Equity in earnings of unconsolidated real estate ventures - gain on sale of real estate assets and purchase of joint venture partner's interest	0	26,923
Income tax (expense) benefit	602	743
Net income (loss)	(10,369)	6,616
Depreciation and amortization expense	720	2,311
Acquisition of real estate assets	(39,136)	(234,820)
Development and redevelopment of real estate assets	$ (5,246)	$ (6,543)