Segment Information - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	$ 291,054	$ 244,249
Cost of service revenue	188,618	154,370
General and administrative expenses	92,031	72,011
Operating income	10,405	17,868
Interest expense	(1,450)	(780)
Income before income taxes and noncontrolling interest	8,955	17,088
Income tax expense	977	5,173
Net income	7,978	11,915
Less net income (loss) attributable to noncontrolling interests	2,983	2,448
Net income attributable to LHC Group, Inc.’s common stockholders	4,995	9,467
Total assets	805,323	642,725	$ 793,702
Home health services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	204,187	180,658
Cost of service revenue	130,161	112,086
General and administrative expenses	66,289	53,922
Operating income	7,737	14,650
Interest expense	(1,088)	(585)
Income before income taxes and noncontrolling interest	6,649	14,065
Income tax expense	722	4,253
Net income	5,927	9,812
Less net income (loss) attributable to noncontrolling interests	2,236	2,028
Net income attributable to LHC Group, Inc.’s common stockholders	3,691	7,784
Total assets	530,197	447,807
Community-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	14,091	10,541
Cost of service revenue	10,790	7,948
General and administrative expenses	3,298	2,311
Operating income	3	282
Interest expense	(72)	(39)
Income before income taxes and noncontrolling interest	(69)	243
Income tax expense	(15)	83
Net income	(54)	160
Less net income (loss) attributable to noncontrolling interests	21	8
Net income attributable to LHC Group, Inc.’s common stockholders	(75)	152
Total assets	47,819	32,961
Hospice Services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	42,626	35,948
Cost of service revenue	28,018	23,273
General and administrative expenses	13,298	10,406
Operating income	1,310	2,269
Interest expense	(218)	(117)
Income before income taxes and noncontrolling interest	1,092	2,152
Income tax expense	111	659
Net income	981	1,493
Less net income (loss) attributable to noncontrolling interests	417	286
Net income attributable to LHC Group, Inc.’s common stockholders	564	1,207
Total assets	157,338	126,068
Facility-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	30,150	17,102
Cost of service revenue	19,649	11,063
General and administrative expenses	9,146	5,372
Operating income	1,355	667
Interest expense	(72)	(39)
Income before income taxes and noncontrolling interest	1,283	628
Income tax expense	159	178
Net income	1,124	450
Less net income (loss) attributable to noncontrolling interests	309	126
Net income attributable to LHC Group, Inc.’s common stockholders	815	324
Total assets	$ 69,969	$ 35,889