Subsequent Events (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015 bed	Mar. 31, 2014	Apr. 29, 2015	Apr. 28, 2015 bed
Subsequent Event [Line Items]
Cash dividend per share of common stock declared	$ 0.62	$ 0.57
Number of vacant beds at idle facilities marketed to potential customers	4,400
Subsequent Event
Subsequent Event [Line Items]
Cash dividend per share of common stock declared			$ 0.62
Number of vacant beds at idle facilities marketed to potential customers				1,740