Income Taxes Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Effective Tax Rate	24.40%		32.10%	(2.90%)	32.50%
PROVISION/ (BENEFIT) FOR INCOME TAXES	$ 23,317		$ 28,451	$ (8,287)	$ 87,258
U.S Federal Statutory Income Tax Rate								35.00%
Income Taxes Paid				48,301	66,683
Unrecognized Tax Benefits	9,914			9,914
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	9,006			9,006
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	1,249		$ 1,083	1,249	$ 1,083
Minimum [Member]
Expiration of statutes of limitations impact on UTB balance	500			500
Maximum [Member]
Expiration of statutes of limitations impact on UTB balance	1,500			$ 1,500
Scenario, Forecast [Member]
U.S Federal Statutory Income Tax Rate						21.00%	28.00%
Tax Cuts and Jobs Act [Member]
PROVISION/ (BENEFIT) FOR INCOME TAXES	(8,746)	$ (96,766)
Measurement period adjustment of income tax benefit recorded in prior period	$ (800)