Summary of Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Table Text Block]

The following table summarizes selected Quarterly Financial Data for the Company on a historical basis for the years ended December 31, 2017 and 2016:

(in thousands except per share and per unit data)	First Quarter			Second Quarter	Third Quarter	Fourth Quarter
Year ended December 31, 2017
Operating Data:
Revenue	$	196,131		261,305	262,141	264,749
Net income attributable to common stockholders	$	(33,223	)	48,368	59,666	85,138
Net income attributable to exchangeable operating partnership units	(19		)	104	132	171
Net income attributable to common unit holders	$	(33,242	)	48,472	59,798	85,309
Net income attributable to common stock and unit holders per share and unit:
Basic	$	(0.26	)	0.28	0.35	0.50
Diluted	$	(0.26	)	0.28	0.35	0.50
Year ended December 31, 2016
Operating Data:
Revenue	$	149,628		152,413	152,769	159,561
Net income attributable to common stockholders	$	47,877		34,810	5,305	55,868
Net income attributable to exchangeable operating partnership units	85			64	16	92
Net income attributable to common unit holders	$	47,962		34,874	5,321	55,960
Net income attributable to common stock and unit holders per share and unit:
Basic	$	0.49		0.36	0.05	0.53
Diluted	$	0.49		0.35	0.05	0.53