Income Taxes Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
Effective Tax Rate	22.90%	(90.40%)	20.90%	(25.50%)
Income Tax Expense (Benefit)	$ 20,219,000	$ (76,557,000)	$ 40,034,000	$ (46,412,000)
Federal Statutory Income Tax Rate, Percent						28.00%
Income Taxes Paid, Net			25,211,000	38,163,000
Unrecognized Tax Benefits	10,719,000		10,719,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	9,967,000		9,967,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	1,431,000	$ 1,318,000	1,431,000	1,318,000
Minimum [Member]
Expiration of statutes of limitations impact on UTB balance	500,000		500,000
Maximum [Member]
Expiration of statutes of limitations impact on UTB balance	1,500,000		$ 1,500,000
Tax Cuts and Jobs Act [Member]
Income Tax Expense (Benefit)				$ (97,516,000)
Measurement period adjustment of income tax benefit recorded in prior period	$ 0
Scenario, Forecast [Member]
Federal Statutory Income Tax Rate, Percent					21.00%