Income Taxes Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2016
PROVISION FOR INCOME TAXES	$ 22,651	$ 23,317	$ (60,413)	$ 28,809	$ 33,903	$ 28,451	$ 29,668	$ 29,139		$ 14,364		$ 121,161	$ 111,669
Computed expected tax expense										28.10%	35.00%	35.00%	35.00%
Deferred tax adjustments resulting from Tax Cuts and Jobs Act, rate reconciliation										(24.20%)		(0.00%)	(0.00%)
SAB118 Measurement Period Adjustments Effect on Tax Rate										(1.70%)
Deferred Tax Assets, Valuation Allowance	515				357					$ 515		$ 357
Income Taxes Paid										60,382		96,074	$ 90,307
Unrecognized Tax Benefits	10,227				5,449					10,227		5,449	7,421
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	9,366				3,990					9,366		3,990
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	1,279				$ 995					1,279		995
Income Tax penalties and interest expense (or benefits) included in income tax provision										165		$ (105)	$ 47
Tax Cuts and Jobs Act [Member]
PROVISION FOR INCOME TAXES										(118,367)
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards	4,338									4,338
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	1,042									1,042
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]
Computed expected tax expense									21.00%