CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Rental income	$ 166,647,000	$ 163,997,000	$ 333,090,000	$ 325,419,000
Residents fees and services	98,366,000	97,370,000	196,484,000	194,323,000
Total revenues	265,013,000	261,367,000	529,574,000	519,742,000
Expenses:
Property operating expenses	102,795,000	97,474,000	203,851,000	195,422,000
Depreciation and amortization	69,669,000	71,372,000	142,844,000	142,594,000
General and administrative	22,922,000	11,965,000	38,005,000	22,828,000
Acquisition and certain other transaction related costs	0	180,000	292,000	619,000
Impairment of assets	5,082,000	4,961,000	5,082,000	12,351,000
Total expenses	200,468,000	185,952,000	390,074,000	373,814,000
Operating income	64,545,000	75,415,000	139,500,000	145,928,000
Dividend income	659,000	789,000	1,319,000	789,000
Interest and other income	76,000	177,000	195,000	242,000
Interest expense	(40,800,000)	(41,118,000)	(84,289,000)	(80,399,000)
Loss on early extinguishment of debt	(7,353,000)	0	(7,353,000)	(6,000)
Income from continuing operations before income tax expense and equity in earnings of an investee	17,127,000	35,263,000	49,372,000	66,554,000
Income tax expense	(99,000)	(108,000)	(191,000)	(202,000)
Equity in earnings of an investee	374,000	17,000	502,000	94,000
Income before gain on sale of properties	17,402,000	35,172,000	49,683,000	66,446,000
Gain on sale of properties	0	4,061,000	0	4,061,000
Net income	17,402,000	39,233,000	49,683,000	70,507,000
Net income attributable to noncontrolling interest	(1,360,000)	0	(1,486,000)	0
Net income attributable to common shareholders	16,042,000	39,233,000	48,197,000	70,507,000
Other comprehensive income:
Unrealized gain (loss) on investments in available for sale securities	(4,995,000)	15,931,000	19,050,000	40,118,000
Amounts reclassified from cumulative other comprehensive income to net income	5,082,000	0	5,082,000	0
Equity in unrealized gain of an investee	58,000	43,000	180,000	95,000
Other comprehensive income	145,000	15,974,000	24,312,000	40,213,000
Comprehensive income	17,547,000	55,207,000	73,995,000	110,720,000
Comprehensive income attributable to noncontrolling interest	(1,360,000)	0	(1,486,000)	0
Comprehensive income attributable to common shareholders	$ 16,187,000	$ 55,207,000	$ 72,509,000	$ 110,720,000
Weighted average common shares outstanding (basic) (in shares)	237,399	237,325	237,395	237,320
Weighted average common shares outstanding (diluted) (in shares)	237,445	237,363	237,433	237,349
Per common share amounts (basic and diluted):
Net income attributable to common shareholders (in dollars per share)	$ 0.07	$ 0.17	$ 0.20	$ 0.30