Fair Value Measurements (Details) - USD ($)		1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 15, 2016	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment arrangements					$ 3,000,000		$ 3,000,000		$ 4,600,000
Contingent consideration, current liabilities					2,980,000		2,980,000		4,024,000
Contingent consideration, noncurrent liabilities					0		0		626,000
Change in fair value of contingent consideration, net							(63,000)	$ (2,568,000)
Major Earnout
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accretion related to earnout						$ 1,400,000	$ 0	2,600,000
Provider Earnout
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accretion related to earnout						100,000		100,000
Major Energy Companies | Common Class B | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Share earnout maximum (in shares)							400,000
Provider Companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Earnout period (in months)							9 months
Earnout maximum					9,000,000.0		$ 9,000,000.0
Earnout minimum					5,000,000.0		5,000,000.0
Earnout payments			$ 4,500,000	$ 1,000,000
Major Energy Companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Earnout payments		$ 1,600,000		$ 7,400,000
Major Energy Companies | Major Earnout
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accretion related to earnout					0	1,400,000	0	2,600,000
Change in fair value of contingent consideration, net							100,000
Major Energy Companies | National Gas & Electric, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Earnout period (in months)	33 months
Earnout maximum	$ 20,000,000.0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment arrangements					2,980,000		2,980,000		4,650,000
Fair Value, Measurements, Recurring | Major Stock Earnout
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment arrangements					0		0		0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment arrangements					2,980,000		2,980,000		4,650,000
Accretion related to earnout					0	$ 1,433,000	0	$ 2,660,000
Fair Value, Measurements, Recurring | Level 3 | Major Earnout and Stock Earnout
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment arrangements					$ 2,980,000		2,980,000		$ 4,650,000
Change in fair value of contingent consideration, net							$ (63,000)