Revenue from Contracts with Customers - Narrative (Details) - USD ($)		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative impact of new standard	[1]			$ 754,000
Customer deposits		$ 7,369,000	$ 8,167,000
Contract liabilities		(6,900,000)	$ (11,500,000)
Performance obligation satisfied in previous period		16,800,000
Cash payments received form customers		11,400,000
Contract assets		0
Calculated under Revenue Guidance in Effect before Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract liabilities		$ 5,400,000
Accumulated Deficit
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative impact of new standard	[1]			$ 754,000

[1] Effective January 1, 2018, we adopted Accounting Standard Update No. 2014-09, Revenue from Contracts with Customers. See Note 2. Significant Accounting Policies and Note 3. Revenue from Contracts with Customers for more information.