Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 12, 2017	Dec. 31, 2017	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in retained earnings			$ 11,431		$ (9,414)
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in retained earnings				$ 300
Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in cash and cash equivalents	$ 3,358	$ 3,358