Debt - Credit Facilities (Details) - USD ($)	1 Months Ended		6 Months Ended
	Jan. 31, 2019	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 14, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Repayment of notes payable			$ 4,860,000	$ 1,676,000
Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Repayments of lines of credit	$ 5,000,000
Line of Credit | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing amount		$ 50,000,000
Cash balance for borrowing		100.00%
Cash balance max borrowing		$ 15,000,000.0
Line of credit facility increase		25,000,000.0
Line of credit facility, outstanding		30,000,000
Repayment of notes payable		20,000,000
Line of credit facility, maximum indebtedness under debt covenant		20,000,000.0
Unused borrowing capacity		$ 5,000,000			$ 5,000,000
Line of credit fair value outstanding			$ 31,700,000
Weighted average interest rate			4.33%			4.41%
Unused part of credit facility			$ 13,700,000
Minimum required unused borrowing capacity			$ 5,000,000.0
Line of Credit | Wells Fargo Credit Facility | U.S.
Line of Credit Facility [Line Items]
Liquidity Requirements under Line of Credit Facility					30,000,000
Line of Credit | Wells Fargo Credit Facility | World Wide
Line of Credit Facility [Line Items]
Liquidity Requirements under Line of Credit Facility					$ 40,000,000
Line of Credit | Libor Plus Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Weighted average interest rate			4.33%
Line of Credit | Prime Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Commitment fee		0.25%
Line of Credit | Minimum | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Revolver accounts receivable		80.00%
Line of Credit | Minimum | Libor Plus Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, basis spread		1.50%
Line of Credit | Minimum | Prime Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, basis spread		0.50%
Line of Credit | Maximum | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Revolver accounts receivable		85.00%
Line of Credit | Maximum | Libor Plus Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, basis spread		1.75%
Line of Credit | Maximum | Prime Rate | Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, basis spread		0.75%