Summary of Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017:

(in thousands except per share and per unit data)	First Quarter			Second Quarter	Third Quarter	Fourth Quarter
Year ended December 31, 2018
Operating Data:
Revenue	$	276,693		281,412	278,310	284,560
Net income attributable to common stockholders	$	52,660		47,841	69,722	78,904
Net income attributable to exchangeable operating partnership units	111			100	147	167
Net income attributable to common unit holders	$	52,771		47,941	69,869	79,071
Net income attributable to common stock and unit holders per share and unit:
Basic	$	0.31		0.28	0.41	0.47
Diluted	$	0.31		0.28	0.41	0.46
Year ended December 31, 2017
Operating Data:
Revenue	$	196,131		261,305	262,141	264,749
Net (loss) income attributable to common stockholders	$	(33,223	)	48,368	59,666	85,138
Net (loss) income attributable to exchangeable operating partnership units	(19		)	104	132	171
Net (loss) income attributable to common unit holders	$	(33,242	)	48,472	59,798	85,309
Net (loss) 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