Acquisitions (Details) $ in Thousands			1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	May 31, 2019 USD ($)	Jan. 31, 2019 USD ($)	Jul. 31, 2019 USD ($) item	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($) item	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Cash paid, net of cash acquired						$ 31,585
Issuance of seller notes at fair value						5,053
Goodwill				$ 226,348	$ 198,742	226,348	$ 198,742	$ 196,343
Goodwill						30,112	2,399
2019 Acquisition Activity, prosthetic and orthotic business
Acquisitions
Acquisition-related costs				300		800
Number of businesses acquired | item			2
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Cash paid, net of cash acquired	$ 200	$ 27,700	$ 3,000			30,926
Issuance of seller notes at fair value	300	4,400	300			5,053
Additional consideration				700		659
Aggregate purchase price	$ 500	$ 32,800	$ 3,300			36,638
Accounts receivable, net				3,630		3,630
Inventories				1,693		1,693
Other Assets				(2,687)		(2,687)
Net assets acquired				8,776		8,776
Goodwill				27,862		27,862
Operating right-of-use assets				600		600
Operating lease liabilities				2,000		2,000
2019 Acquisition Activity, prosthetic and orthotic business | Customer Relationships
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Other intangible assets, net				5,791		$ 5,791
Useful life						4 years 10 months 24 days
2019 Acquisition Activity, prosthetic and orthotic business | Non-compete agreements
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Other intangible assets, net				$ 349		$ 349
Useful life						4 years 10 months 24 days
2019 Acquisition Activity, prosthetic and orthotic business | Minimum
Acquisitions
Notes payable to share holders in quarterly installments period						3 years
2019 Acquisition Activity, prosthetic and orthotic business | Maximum
Acquisitions
Notes payable to share holders in quarterly installments period						5 years
2018 Acquisition Activity, two O&P businesses
Acquisitions
Number of businesses acquired | item					2
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Cash paid, net of cash acquired							1,978
Issuance of seller notes at fair value							1,120
Aggregate purchase price							3,098
Accounts receivable, net					$ 256		256
Inventories					302		302
Other assets					90		90
Accounts payable					(59)		(59)
Accrued expenses and other liabilities					(364)		(364)
Net assets acquired					699		699
Goodwill					2,399		2,399
2018 Acquisition Activity, two O&P businesses | Customer Relationships
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Other intangible assets, net					260		$ 260
Useful life							4 years
2018 Acquisition Activity, two O&P businesses | Non-compete agreements
Aggregate purchase price of this acquisition was allocated on a preliminary basis
Other intangible assets, net					$ 214		$ 214
Useful life							4 years 7 months 6 days