Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Student Housing Operations
Revenues from external customers	$ 35,389	$ 24,890	$ 68,266	$ 48,764
Development, Construction and Management Services	16,803	11,333	31,059	21,617
Operating expenses	32,506	23,919	62,776	46,741
Interest expense	2,201	1,360	5,774	2,735
Change in fair value of interest rate derivatives	(55)	141	(104)	337
Other income (expense)	(76)	(2)	(74)	44
Income tax expense	193	107	256	258
Equity in earnings (loss) of unconsolidated entities	102	(284)	198	(526)
Segment operating income (loss)	2,985	687	5,688	1,497
Other income	(2,332)	(1,221)	(5,952)	(2,354)
Net income	460	(641)	(520)	(1,115)
Net loss	14	3	23	5
Net income attributable to stockholders	0	0	0	0
Total assets	604,207		604,207		540,257
Student Housing Operations [Member]
Student Housing Operations
Revenues from external customers	18,586	13,557	37,207	27,147
Operating expenses	14,877	11,410	29,385	23,115
Segment operating income (loss)	3,709	2,147	7,822	4,032
Other income	(1,879)	(639)	(5,129)	(1,539)
Net income	1,830	1,508	2,693	2,493
Net loss	(18)	(15)	(26)	(24)
Net income attributable to stockholders	1,812	1,493	2,667	2,469
Depreciation and amortization	5,803	5,148	11,592	10,245
Total segment assets	555,142	408,661	555,142	408,661
Development Construction and Management Services [Member]
Student Housing Operations
Revenues from external customers	16,803	11,333	31,059	21,617
Elimination of intersegment revenues	26,214	35,348	45,524	51,915
Total segment revenues	43,017	46,681	76,583	73,532
Operating expenses	41,362	42,738	73,346	68,078
Segment operating income (loss)	1,655	3,943	3,237	5,454
Other income	0	(223)	0	(235)
Net income	1,655	3,720	3,237	5,219
Net loss	(16)	(37)	(31)	(52)
Net income attributable to stockholders	1,639	3,683	3,206	5,167
Depreciation and amortization	23	22	45	46
Total segment assets	31,934	13,140	31,934	13,140
Reconciliations [Member]
Student Housing Operations
Development, Construction and Management Services	35,389	24,890	68,266	48,764
Elimination of intersegment revenues	(26,214)	(35,348)	(45,524)	(51,915)
Total segment revenues	61,603	60,238	113,790	100,679
Interest expense	(2,201)	(1,360)	(5,774)	(2,735)
Change in fair value of interest rate derivatives	(55)	141	(104)	337
Income tax expense	(193)	(107)	(256)	(258)
Net unallocated expenses and eliminations	(2,481)	(5,119)	(5,569)	(7,463)
Equity in earnings (loss) of unconsolidated entities	102	(284)	198	(526)
Segment operating income (loss)	5,364	6,090	11,059	9,486
Other income	(76)	(2)	(74)	44
Net loss	460	(641)	(520)	(1,115)
Total segment assets	587,076	421,801	587,076	421,801
Unallocated corporate assets and eliminations	17,131	3,125	17,131	3,125
Total assets	$ 604,207	$ 424,926	$ 604,207	$ 424,926