Earnings per share (Tables)

3 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

			Three Months Ended
			March 31,
(Amounts in thousands, except share and per share amounts)			2012		2011
	Net income attributable to common
		stockholders – basic and diluted	$	19,482	$	18,207
	Weighted average shares outstanding – basic and diluted			5,106,984		5,105,936
	Net income per common share – basic and diluted		$	3.81	$	3.57