Selected Quarterly Financial Data (Unaudited) - Summary of Selected Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Net patient revenues from continuing operations	$ 67,256	$ 64,368	$ 65,227	$ 61,432	$ 61,052	$ 60,719	$ 61,963	$ 60,366	$ 258,283	$ 244,100	$ 225,804
Net revenues from continuing operations	68,605	65,829	66,868	62,756	62,381	62,102	63,397	61,771	264,058	249,651	231,523
Operating income from continuing operations	9,372	9,904	11,059	8,435	8,301	9,534	10,806	9,765	38,770	38,406	31,428
Net income from continuing operations including noncontrolling interests	5,796	6,756	7,642	5,809	6,032	6,423	7,452	6,733	26,003	26,640	26,679
Net income from continuing operations attributable to common shareholders	3,903	4,659	5,079	3,851	4,230	4,588	4,958	4,436	17,492	18,212	18,812
Net losses (income) from discontinued operations attributable to common shareholders	(42)	(4,432)	(165)	(130)	(187)	(25)	(109)	42	(4,769)	(279)	2,162
Net income attributable to common shareholders	$ 3,861	$ 227	$ 4,914	$ 3,721	$ 4,043	$ 4,563	$ 4,849	$ 4,478	$ 12,723	$ 17,933	$ 20,974
Basic earnings per share attributable to common shareholders:
From continuing operations.	$ 0.32	$ 0.38	$ 0.42	$ 0.32	$ 0.35	$ 0.39	$ 0.41	$ 0.37	$ 1.45	$ 1.54	$ 1.60
From discontinued operations		$ (0.36)	$ (0.01)	$ (0.01)	$ (0.02)		$ (0.01)		$ (0.40)	$ (0.02)	$ 0.18
Basic	$ 0.32	$ 0.02	$ 0.41	$ 0.31	$ 0.33	$ 0.39	$ 0.40	$ 0.37	$ 1.05	$ 1.52	$ 1.78
Diluted earnings per share attributable to common shareholders:
From continuing operations.	$ 0.32	$ 0.38	$ 0.42	$ 0.32	$ 0.35	$ 0.38	$ 0.41	$ 0.37	$ 1.45	$ 1.53	$ 1.57
From discontinued operations		$ (0.36)	$ (0.01)	$ (0.01)	$ (0.02)		$ (0.01)		$ (0.40)	$ (0.02)	$ 0.18
Diluted	$ 0.32	$ 0.02	$ 0.41	$ 0.31	$ 0.33	$ 0.38	$ 0.40	$ 0.37	$ 1.05	$ 1.51	$ 1.75
Shares used in computation:
Basic	12,103	12,106	12,089	11,955	12,103	12,106	12,089	11,955	12,063	11,804	11,814
Diluted	12,117	12,120	12,110	11,979	12,117	12,120	12,110	11,979	12,082	11,904	11,977