Acquisitions of Businesses (Details) | Oct. 31, 2017USD ($)ClinicInstallment | Jun. 30, 2017USD ($)ClinicInstallment | May 31, 2017USD ($)ClinicInstallment | Mar. 23, 2017USD ($) | Jan. 01, 2017USD ($)ClinicInstallment | Nov. 30, 2016USD ($)ClinicInstallment | Feb. 29, 2016USD ($)ClinicInstallment | Dec. 31, 2015USD ($)ClinicInstallment | Aug. 31, 2015USD ($) | Jun. 30, 2015USD ($)Clinic | Apr. 30, 2015USD ($)ClinicInstallment | Jan. 31, 2015USD ($)ClinicInstallment | Dec. 31, 2017USD ($)ClinicContractOperation | Dec. 31, 2016USD ($)ClinicSubsidiary | Dec. 31, 2015USD ($)Clinic |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Number of management contracts | Contract | | | | | | | | | | | | | 2 | | |
Number of clinics consolidated with an existing clinic | Clinic | | | | | | | | | | | | | 1 | | |
Number of clinics that operate as a satellite clinic with existing partnerships | Clinic | | | | | | | | | | | | | 1 | | |
Percentage of interest acquired | | | | | | | | | | | | | 35.00% | | |
Number of clinics | Clinic | | | | | | | | | | | | | 2 | | |
Seller notes issued for acquisition of interest in clinic | | | | | | | | $ 1,800,000 | | | | | $ 2,150,000 | $ 1,000,000 | $ 1,800,000 |
Number of acquired operations combined | Operation | | | | | | | | | | | | | 2 | | |
Cash paid, net of cash acquired | | | | | | | | | | | | | $ 36,682,000 | 23,623,000 | 18,965,000 |
Seller notes | | | | | | | | 1,800,000 | | | | | 2,150,000 | 1,000,000 | 1,800,000 |
Total consideration | | | | | | | | 20,765,000 | | | | | 38,832,000 | 24,623,000 | 20,765,000 |
Estimated fair value of net tangible assets acquired: [Abstract] | | | | | | | | | | | | | | | |
Total current assets | | | | | | | | 1,952,000 | | | | | 6,248,000 | 1,372,000 | 1,952,000 |
Total non-current assets | | | | | | | | 1,068,000 | | | | | 1,818,000 | 839,000 | 1,068,000 |
Total liabilities | | | | | | | | (1,067,000) | | | | | (2,909,000) | (399,000) | (1,067,000) |
Net tangible assets acquired | | | | | | | | 1,953,000 | | | | | 5,157,000 | 1,812,000 | 1,953,000 |
Referral relationships | | | | | | | | 3,655,000 | | | | | 3,885,000 | 4,919,000 | 3,655,000 |
Non-compete | | | | | | | | 594,000 | | | | | 1,224,000 | 847,000 | 594,000 |
Tradename | | | | | | | | 3,417,000 | | | | | 8,439,000 | 3,802,000 | 3,417,000 |
Goodwill | | | | | | | | 23,437,000 | | | | | 44,292,000 | 32,123,000 | 23,437,000 |
Fair value of non-controlling interest (classified as redeemable non-controlling interests) | | | | | | | | | | | | | (13,883,000) | | |
Fair value of non-controlling interest (originally classified as mandatorily redeemable non-controlling interests) | | | | | | | | (12,291,000) | | | | | (10,282,000) | (18,880,000) | (12,291,000) |
Total consideration | | | | | | | | $ 20,765,000 | | | | | $ 38,832,000 | $ 24,623,000 | $ 20,765,000 |
Minimum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | | 5.00% | | | | | | 2.00% | 5.00% |
Maximum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | | 35.00% | | | | | | 35.00% | 35.00% |
Referral Relationships [Member] | Minimum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Estimated useful lives of acquired intangibles | | | | | | | | | | | | | 7 years 6 months | | |
Referral Relationships [Member] | Maximum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Estimated useful lives of acquired intangibles | | | | | | | | | | | | | 13 years | | |
Non-compete Agreements [Member] | Minimum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Estimated useful lives of acquired intangibles | | | | | | | | | | | | | 5 years | | |
Non-compete Agreements [Member] | Maximum [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Estimated useful lives of acquired intangibles | | | | | | | | | | | | | 6 years | | |
Tradenames [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Estimated useful lives of acquired intangibles | | | | | | | | | | | | | 6 years | | |
February 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | | | | | $ 194,000 | |
February 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | | | | | $ 194,000 | |
Acquisition of Seventeen Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | | | | | | | | 70.00% | |
Number of clinics | Clinic | | | | | 17 | | | | | | | | | | |
Cash paid for acquisition of interest in clinic | | | | | $ 10,700,000 | | | | | | | | | | |
Seller notes issued for acquisition of interest in clinic | | | | | | | | | | | | | | $ 500,000 | |
Business acquisition number of installments to payment of purchase consideration | Installment | | | | | 2 | | | | | | | | | | |
Seller notes | | | | | | | | | | | | | | $ 500,000 | |
Acquisition of Seventeen Clinic Practices [Member] | January 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | $ 250,000 | | | | | | | | | | |
Acquisition of Seventeen Clinic Practices [Member] | January 2019 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | $ 250,000 | | | | | | | | | | |
Workforce Performance Solutions [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | 55.00% | | | | | | | | | | | |
Cash paid for acquisition of interest in clinic | | | | $ 6,200,000 | | | | | | | | | | | |
Seller notes issued for acquisition of interest in clinic | | | | 400,000 | | | | | | | | | | | |
Seller notes | | | | $ 400,000 | | | | | | | | | | | |
January 2017 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | Jan. 1, 2017 | | |
Percentage of interest acquired | | | | | | | | | | | | | 70.00% | | |
Number of clinics | Clinic | | | | | | | | | | | | | 17 | | |
May 2017 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | May 31, 2017 | | |
Percentage of interest acquired | | | | | | | | | | | | | 70.00% | | |
Number of clinics | Clinic | | | | | | | | | | | | | 4 | | |
June 2017 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | Jun. 30, 2017 | | |
Percentage of interest acquired | | | | | | | | | | | | | 60.00% | | |
Number of clinics | Clinic | | | | | | | | | | | | | 9 | | |
October 2017 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | Oct. 31, 2017 | | |
Percentage of interest acquired | | | | | | | | | | | | | 70.00% | | |
Number of clinics | Clinic | | | | | | | | | | | | | 9 | | |
February 2016 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | Feb. 29, 2016 | |
Percentage of interest acquired | | | | | | | | | | | | | | 55.00% | |
Number of clinics | Clinic | | | | | | | | | | | | | | 8 | |
November 2016 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | Nov. 30, 2016 | |
Percentage of interest acquired | | | | | | | | | | | | | | 60.00% | |
Number of clinics | Clinic | | | | | | | | | | | | | | 12 | |
January 2015 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | | Jan. 31, 2015 |
Percentage of interest acquired | | | | | | | | 60.00% | | | | | | | 60.00% |
Number of clinics | Clinic | | | | | | | | | | | | | | | 9 |
April 2015 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | | Apr. 30, 2015 |
Percentage of interest acquired | | | | | | | | 70.00% | | | | | | | 70.00% |
Number of clinics | Clinic | | | | | | | | | | | | | | | 3 |
June 2015 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | | Jun. 30, 2015 |
Percentage of interest acquired | | | | | | | | 70.00% | | | | | | | 70.00% |
Number of clinics | Clinic | | | | | | | | | | | | | | | 4 |
December 2015 Acquisition [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition date | | | | | | | | | | | | | | | Dec. 31, 2015 |
Percentage of interest acquired | | | | | | | | 59.00% | | | | | | | 59.00% |
Number of clinics | Clinic | | | | | | | | | | | | | | | 4 |
Acquisition Of Single Clinic Practice [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | | | 60.00% | | | | | | |
Cash paid for acquisition of interest in clinic | | | | | | | | | $ 150,000 | | | | | | |
Seller notes issued for acquisition of interest in clinic | | | | | | | | | 50,000 | | | | | | |
Aggregate purchase price for the acquired clinic practices | | | | | | | | | | | | | | $ 75,000 | |
Number of subsidiaries acquired clinic practices | Subsidiary | | | | | | | | | | | | | | 2 | |
Seller notes | | | | | | | | | 50,000 | | | | | | |
Acquisition Of Single Clinic Practice [Member] | August 2016 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | $ 50,000 | | | | | | |
Acquisition Of Three Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | | | | | 70.00% | | | | |
Number of clinics | Clinic | | | | | | | | | | | 3 | | | | |
Cash paid for acquisition of interest in clinic | | | | | | | | | | | $ 4,700,000 | | | | |
Seller notes issued for acquisition of interest in clinic | | | | | | | | | | | $ 150,000 | | | | |
Business acquisition number of installments to payment of purchase consideration | Installment | | | | | | | | | | | 2 | | | | |
Seller notes | | | | | | | | | | | $ 150,000 | | | | |
Acquisition Of Three Clinic Practices [Member] | April 2016 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | | 75,000 | | | | |
Acquisition Of Three Clinic Practices [Member] | April 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | | $ 75,000 | | | | |
Acquisition Of Four Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | 70.00% | | | | | 59.00% | | 70.00% | | | | | 59.00% |
Number of clinics | Clinic | | | 4 | | | | | 4 | | 4 | | | | | |
Cash paid for acquisition of interest in clinic | | | $ 2,300,000 | | | | | $ 4,600,000 | | $ 3,600,000 | | | | | |
Seller notes issued for acquisition of interest in clinic | | | $ 250,000 | | | | | $ 400,000 | | 700,000 | | | | | $ 400,000 |
Business acquisition number of installments to payment of purchase consideration | Installment | | | 2 | | | | | 2 | | | | | | | |
Seller notes | | | $ 250,000 | | | | | $ 400,000 | | 700,000 | | | | | $ 400,000 |
Acquisition Of Four Clinic Practices [Member] | May 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | 125,000 | | | | | | | | | | | | |
Acquisition Of Four Clinic Practices [Member] | May 2019 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | $ 125,000 | | | | | | | | | | | | |
Acquisition Of Four Clinic Practices [Member] | June 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | $ 700,000 | | | | | |
Acquisition Of Four Clinic Practices [Member] | December 2016 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | 200,000 | | | | | | | |
Acquisition Of Four Clinic Practices [Member] | December 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | $ 200,000 | | | | | | | |
Acquisition Of Eight Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | | 55.00% | | | | | | | | |
Number of clinics | Clinic | | | | | | | 8 | | | | | | | | |
Cash paid for acquisition of interest in clinic | | | | | | | $ 13,200,000 | | | | | | | | |
Seller notes issued for acquisition of interest in clinic | | | | | | | $ 500,000 | | | | | | | | |
Business acquisition number of installments to payment of purchase consideration | Installment | | | | | | | 2 | | | | | | | | |
Seller notes | | | | | | | $ 500,000 | | | | | | | | |
Acquisition Of Eight Clinic Practices [Member] | February 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | 250,000 | | | | | | | | |
Acquisition Of Eight Clinic Practices [Member] | February 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | $ 250,000 | | | | | | | | |
Acquisition Of Nine Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | 70.00% | 60.00% | | | | | | | | | | 60.00% | | | |
Number of clinics | Clinic | 9 | 9 | | | | | | | | | | 9 | | | |
Cash paid for acquisition of interest in clinic | $ 4,000,000 | $ 15,800,000 | | | | | | | | | | $ 6,700,000 | | | |
Seller notes issued for acquisition of interest in clinic | $ 500,000 | $ 500,000 | | | | | | | | | | $ 500,000 | | | |
Business acquisition number of installments to payment of purchase consideration | Installment | 2 | 2 | | | | | | | | | | 2 | | | |
Seller notes | $ 500,000 | $ 500,000 | | | | | | | | | | $ 500,000 | | | |
Acquisition Of Nine Clinic Practices [Member] | June 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | 250,000 | | | | | | | | | | | | | |
Acquisition Of Nine Clinic Practices [Member] | June 2019 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | $ 250,000 | | | | | | | | | | | | | |
Acquisition Of Nine Clinic Practices [Member] | October 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | 250,000 | | | | | | | | | | | | | | |
Acquisition Of Nine Clinic Practices [Member] | October 2019 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | $ 250,000 | | | | | | | | | | | | | | |
Acquisition Of Nine Clinic Practices [Member] | January 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | | | | | | | $ 250,000 | | | |
Acquisition Of Twelve Clinic Practices [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Percentage of interest acquired | | | | | | 60.00% | | | | | | | | | |
Number of clinics | Clinic | | | | | | 12 | | | | | | | | | |
Cash paid for acquisition of interest in clinic | | | | | | $ 11,000,000 | | | | | | | | | |
Seller notes issued for acquisition of interest in clinic | | | | | | $ 500,000 | | | | | | | | | |
Business acquisition number of installments to payment of purchase consideration | Installment | | | | | | 2 | | | | | | | | | |
Seller notes | | | | | | $ 500,000 | | | | | | | | | |
Acquisition Of Twelve Clinic Practices [Member] | November 2017 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | 250,000 | | | | | | | | | |
Acquisition Of Twelve Clinic Practices [Member] | November 2018 [Member] | | | | | | | | | | | | | | | |
Business Acquisition [Line Items] | | | | | | | | | | | | | | | |
Acquisition cost payable in two principal installments including accrued interest | | | | | | $ 250,000 | | | | | | | | | |