CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows provided by operating activities:
Net income	$ 41,982	$ 38,192	$ 27,525
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	32,519	34,847	35,925
(Benefit) provision for doubtful accounts	(54)	295	1,131
Share-based compensation expense	12,297	18,448	13,414
Deferred income taxes	5,613	17,432	(3,226)
Amortization of debt discounts and issuance costs	1,932	2,085	1,623
Gain on sale and disposal of fixed assets	(1,340)	(3,134)	(1,614)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable, net	(17,315)	34,378	(12,329)
Inventories	(6,350)	(6,258)	1,568
Other current assets and other assets	(5,736)	(628)	(2,611)
Income taxes receivable	12,307	(13,757)	1,248
Accounts payable	(1,909)	14,674	(6,725)
Accrued expenses and other current liabilities	(6,351)	217	(1,242)
Accrued compensation related costs	(18,420)	11,349	5,780
Other liabilities	(11,079)	4,778	(1,883)
Operating lease liabilities, net of amortization of right-of-use assets	(1,886)	2,649	262
Changes in operating assets and liabilities:	(56,739)	47,402	(15,932)
Net cash provided by operating activities	36,210	155,567	58,846
Cash flows used in investing activities:
Acquisitions, net of cash acquired	(80,078)	(21,801)	(36,585)
Purchase of property, plant, and equipment	(22,579)	(24,500)	(26,433)
Purchase of therapeutic program equipment leased to third parties under operating leases	(2,280)	(3,592)	(6,672)
Proceeds from sale of property, plant and equipment	2,451	3,890	2,598
Other investing activities, net	0	135	(66)
Net cash used in investing activities	(102,486)	(45,868)	(67,158)
Cash flows used in financing activities:
Borrowings under revolving credit agreement	0	79,000	0
Repayments under revolving credit agreement	0	(79,000)	0
Repayment of term loan	(5,050)	(5,050)	(5,050)
Payment of employee taxes on stock-based compensation	(4,674)	(7,356)	(4,137)
Payment of Seller Notes and additional consideration	(4,434)	(25,415)	(3,821)
Payments under vendor financing arrangements	(1,375)	(825)	0
Payment of financing lease obligations	(1,052)	(748)	(474)
Payment of debt issuance costs	(573)	(214)	0
Proceeds from exercise of options	524	92	1,099
Net cash used in financing activities	(16,634)	(39,516)	(12,383)
(Decrease) increase in cash and cash equivalents	(82,910)	70,183	(20,695)
Cash and cash equivalents at beginning of period	144,602	74,419	95,114
Cash and cash equivalents at end of period	61,692	144,602	74,419
Reconciliation of the Change in Operating Lease Liabilities, Net of Amortization of Right-of-Use Assets [Abstract]
Operating lease liabilities	(43,346)	(37,343)	(36,911)
Amortization of right-of-use assets	41,460	39,992	37,173
Operating lease liabilities, net of amortization of right-of-use assets	(1,886)	2,649	262
Cash paid during the period for:
Interest paid	25,727	28,411	29,192
Income tax (refunds received) paid	(11,296)	(2,979)	5,100
Non-cash financing and investing activities:
Seller Notes, deferred payment obligations and additional consideration related to acquisitions	24,395	31,579	7,885
Purchase of property, plant and equipment in accounts payable at period end	3,396	3,955	2,998
Purchase of property, plant and equipment through vendor financing	$ 0	$ 0	$ 2,200