Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)	Jan. 01, 2019 USD ($) item
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, Practical Expedients, Package [true false]	true
Lease, Practical Expedient, Use of Hindsight [true false]	false
Right-of use assets for operating leases	$ 2,598
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets
Lease liabilities for operating leases	$ 2,616
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accounts Payable and Other Accrued Liabilities
Number of leased properties | item		5
Number of leased pieces of equipment | item		6
ASU 2016‑02 | Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of use assets for operating leases		$ 2,700
Lease liabilities for operating leases		$ 2,700