Significant Transactions - Consideration and Allocation (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 02, 2020	Jan. 02, 2020	Dec. 31, 2019	Jan. 02, 2019	Dec. 31, 2018
Estimated fair values of net assets acquired
Cash		$ 117,000
Accounts receivables		3,691,000
Inventory		3,610,000
Prepaid and other current assets		12,000
Equipment and other fixed assets		5,229,000
Other assets		110,000
Goodwill	$ 342,851,000	21,951,000			$ 266,791,000
Accounts payable and accrued expenses		(2,266,000)
Contract liabilities		(1,186,000)
Net assets acquired		31,268,000
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination [Abstract]
Equity consideration issued in connection with an acquisition	6,248,000
Liability incurred		2,000,000
Contingent consideration obligations	10,825,000	4,750,000			$ 14,725,000		$ 15,250,000
Deferred payments/contingent consideration		1,500,000
Receipt of working capital adjustment from 2018 acquisitions		318,000
Significant Acquisitions In 2020 [Member]
Estimated fair values of net assets acquired
Cash	736,000
Accounts receivables	20,118,000
Inventory	4,413,000
Prepaid and other current assets	1,334,000
Equipment and other fixed assets	25,264,000
Goodwill	76,060,000
Accounts payable and accrued expenses	(6,493,000)
Contract liabilities	(3,906,000)
Unfavorable lease liability	(1,419,000)
Capital lease obligations	(1,627,000)
Net assets acquired	114,480,000
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination [Abstract]
Cash payment	108,199,000
Equity consideration issued in connection with an acquisition	6,248,000
Deferred payments/contingent consideration	33,000
Total consideration	$ 114,480,000
Patient Care Solutions (PCS) [Member]
Business Acquisition
Interest acquired, as a percent				100.00%
Estimated fair values of net assets acquired
Accounts receivables				$ 16,300,000
Equipment and other fixed assets				500,000
Goodwill				1,400,000
Accounts payable and accrued expenses				$ (3,200,000)
Advanced Home Care Inc [Member]
Estimated fair values of net assets acquired
Inventory			$ 2,700,000
Equipment and other fixed assets			18,400,000
Goodwill			39,600,000
Accounts payable and accrued expenses			(2,200,000)
Potential contingent payment			$ 9,000,000.0
Significant acquisitions in 2019
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination [Abstract]
Cash payment		27,768,000
Liability incurred		2,000,000
Deferred payments/contingent consideration		1,500,000
Total consideration		31,268,000
Gould's
Business Acquisition
Interest acquired, as a percent						100.00%
Estimated fair values of net assets acquired
Accounts receivables		3,700,000
Inventory		2,400,000
Equipment and other fixed assets		1,700,000
Goodwill		19,100,000
Accounts payable and accrued expenses		$ (2,600,000)