Long-Term Obligations (Details Textual) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended			0 Months Ended	9 Months Ended		21 Months Ended
	Jan. 25, 2012	Aug. 31, 2011	Aug. 31, 2010	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 27, 2014	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Aug. 31, 2014	Apr. 30, 2013
Debt Instrument [Line Items]
Credit facility available			$ 600,000,000
Face amount of debt instrument		581,300,000	500,000,000
Maximum borrowing capacity under credit agreement		125,000,000	100,000,000	800,000,000
Financing costs incurred	122,000	2,900,000	9,100,000	7,987,000	0	122,000
Debt retirement expenses recognized as part of income from continuing operations	47,000	865,000	2,100,000
Deferred charges	75,000	2,000,000
Amount capitalized as deferred financing costs			1,300,000
Proceeds from issuance of debt	50,000,000.0	100,000,000
Increase in incremental facilities	50,000,000.0
Incremental facilities after amendment	100,000,000.0
Additional revolving commitment under new facility		25,000,000
Deferred financing costs capitalized				7,874,000	2,987,000
Write-off of previously capitalized deferred financing costs		1,100,000
Debt obligation				735,230,000	557,144,000
Stock repurchase program, amount				400,000,000							400,000,000.0	125,000,000.0
Voting equity guarantee on indebtedness, percentage				65.00%
Non-voting guarantee on indebtedness, percentage				100.00%
Covenant compliance, interest coverage ratio				21.00
Covenant terms, minimum interest coverage ratio				3
Covenant compliance, leverage ratio				2.19
Covenant terms, maximum leverage ratio				4.5
Senior Notes [Member]
Debt Instrument [Line Items]
Debt obligation				600,000,000	556,914,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Financing costs incurred							8,000,000
Deferred financing costs capitalized							6,500,000
Debt related expense recognized as income from continuing operations							1,500,000
Write-off of previously capitalized deferred financing costs							200,000
Credit Agreement [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							600,000,000
Senior Credit Facility [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							534,000,000
Secured debt [Member] | Credit Agreement [Member] | Line of credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							1,400,000,000.0
Revolving line of credit [Member]
Debt Instrument [Line Items]
Debt obligation				135,000,000	0
Revolving line of credit [Member] | Credit Agreement [Member] | Line of credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							800,000,000
Revolving line of credit [Member] | Senior Credit Facility [Member] | Line of credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							125,000,000
Swing line [Member] | Credit Agreement [Member] | Line of credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity under credit agreement							25,000,000
Forecast [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Principal payment (quarterly)								$ 15,000,000	$ 11,300,000	$ 7,500,000