BUSINESS COMBINATIONS AND RELATED ACTIVITY (Details - Assets Acquired and Liabilities Assumed) - USD ($) $ in Thousands		9 Months Ended
	Aug. 24, 2021	Sep. 30, 2021	Jun. 01, 2021	May 01, 2021	Apr. 01, 2021	Mar. 01, 2021	Feb. 01, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill		$ 502,710						$ 472,879
Personal Health Imaging PLLC
Business Acquisition [Line Items]
Total Consideration							$ 2,995
Property & Equipment							576
Right of Use Assets							608
Goodwill							2,355
Intangible Assets							50
Other Assets							14
Right of Use Liabilities							(608)
ZP Elmont LLC
Business Acquisition [Line Items]
Total Consideration							2,194
Property & Equipment							1,112
Right of Use Assets							0
Goodwill							1,005
Intangible Assets							50
Other Assets							27
Right of Use Liabilities							0
ZP Freeport LLC
Business Acquisition [Line Items]
Total Consideration							6,065
Property & Equipment							4,668
Right of Use Assets							0
Goodwill							1,328
Intangible Assets							40
Other Assets							29
Right of Use Liabilities							0
Broadway Medical Imaging LLC
Business Acquisition [Line Items]
Total Consideration							1,155
Property & Equipment							1,076
Right of Use Assets							446
Goodwill							6
Intangible Assets							50
Other Assets							23
Right of Use Liabilities							(446)
3235 Hempstead LLC
Business Acquisition [Line Items]
Total Consideration							9,386
Property & Equipment							5,667
Right of Use Assets							0
Goodwill							3,649
Intangible Assets							70
Other Assets							0
Right of Use Liabilities							0
SLZM Realty LLC
Business Acquisition [Line Items]
Total Consideration							13,671
Property & Equipment							4,617
Right of Use Assets							0
Goodwill							8,974
Intangible Assets							80
Other Assets							0
Right of Use Liabilities							0
2012 Sunrise Merrick LLC
Business Acquisition [Line Items]
Total Consideration							11,428
Property & Equipment							2,741
Right of Use Assets							335
Goodwill							8,617
Intangible Assets							70
Other Assets							0
Right of Use Liabilities							$ (335)
ZP Bayside LLC
Business Acquisition [Line Items]
Total Consideration						$ 3,545
Property & Equipment						3,385
Right of Use Assets						2,191
Goodwill						40
Intangible Assets						50
Other Assets						70
Right of Use Liabilities						(2,191)
ZP Laurelton LLC
Business Acquisition [Line Items]
Total Consideration						2,658
Property & Equipment						2,530
Right of Use Assets						1,418
Goodwill						32
Intangible Assets						50
Other Assets						46
Right of Use Liabilities						(1,418)
ZP Smith LLC
Business Acquisition [Line Items]
Total Consideration						3,978
Property & Equipment						3,581
Right of Use Assets						2,214
Goodwill						347
Intangible Assets						50
Other Assets						0
Right of Use Liabilities						$ (2,214)
ZP 907 Northern LLC
Business Acquisition [Line Items]
Total Consideration					$ 562
Property & Equipment					507
Right of Use Assets					1,817
Goodwill					5
Intangible Assets					50
Other Assets					0
Right of Use Liabilities					$ (1,817)
William M. Kelly MD, Inc.
Business Acquisition [Line Items]
Total Consideration				$ 3,750
Property & Equipment				990
Right of Use Assets				1,379
Goodwill				2,710
Intangible Assets				50
Other Assets				0
Right of Use Liabilities				(1,379)
60th Street MRI, LLC
Business Acquisition [Line Items]
Total Consideration				400
Property & Equipment				85
Right of Use Assets				0
Goodwill				290
Intangible Assets				25
Other Assets				0
Right of Use Liabilities				0
ZP Parkchester LLC
Business Acquisition [Line Items]
Total Consideration				263
Property & Equipment				213
Right of Use Assets				311
Goodwill				0
Intangible Assets				50
Other Assets				0
Right of Use Liabilities				$ (311)
ZP Eastern LLC
Business Acquisition [Line Items]
Total Consideration			$ 2,868
Property & Equipment			2,801
Right of Use Assets			1,951
Goodwill			17
Intangible Assets			50
Other Assets			0
Right of Use Liabilities			$ (1,951)
Tangent Associates LLC
Business Acquisition [Line Items]
Total Consideration	$ 2,025
Property & Equipment	10
Right of Use Assets	0
Goodwill	379
Intangible Assets	1,636
Other Assets	0
Right of Use Liabilities	$ 0
Shares issued (in shares)	67,658
Business Acquisitions
Business Acquisition [Line Items]
Total Consideration		66,943
Property & Equipment		34,559
Right of Use Assets		12,670
Goodwill		29,754
Intangible Assets		2,421
Other Assets		209
Right of Use Liabilities		$ (12,670)
Shares issued (in shares)		67,658