Segment Information - Reconciliation of Operating Income from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 547,800	$ 547,396	$ 473,565	$ 564,020	$ 669,577	$ 652,416	$ 559,443	$ 483,279	$ 2,132,781	$ 2,364,715	$ 1,687,591
Depreciation and amortization									53,336	49,672	49,840
Capital expenditures									94,613	77,626	44,940
Operating income	$ 17,681	$ 24,459	$ 19,036	$ 22,689	$ 37,973	$ 51,234	$ 33,358	$ 26,423	83,865	148,988	56,013
Restructuring charges and other exit-related activities									365	(661)	(109)
Interest expense									(8,266)	(8,983)	(8,081)
Other income, net									641	1,848	758
Income from continuing operations before income taxes									76,240	141,853	48,690
AMR
Segment Reporting Information [Line Items]
Revenues									1,673,365	1,884,074	1,347,971
Operating Segments | AMR
Segment Reporting Information [Line Items]
Revenues									1,684,977	1,908,966	1,363,618
Operating Segments | CSS
Segment Reporting Information [Line Items]
Revenues									459,416	480,641	339,620
Less: Intersegment revenues
Segment Reporting Information [Line Items]
Revenues									(11,612)
Less: Intersegment revenues | AMR
Segment Reporting Information [Line Items]
Revenues									(11,612)	(24,892)	(15,647)
Continuing Operations
Segment Reporting Information [Line Items]
Depreciation and amortization									53,336	49,672	49,840
Capital expenditures									94,613	77,626	44,940
Operating income									83,865	148,988	56,013
Restructuring charges and other exit-related activities									(365)	661	109
Interest expense									(8,266)	(8,983)	(8,081)
Other income, net									641	1,848	758
Income from continuing operations before income taxes									76,240	141,853	48,690
Continuing Operations | AMR
Segment Reporting Information [Line Items]
Operating income									95,991	169,120	91,405
Continuing Operations | CSS
Segment Reporting Information [Line Items]
Operating income									31,951	38,286	5,275
Continuing Operations | Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization									50,597	47,288	47,378
Capital expenditures									94,051	76,699	44,799
Operating income									127,942	207,406	96,680
Continuing Operations | Operating Segments | AMR
Segment Reporting Information [Line Items]
Depreciation and amortization									38,816	35,564	34,853
Capital expenditures									78,706	67,099	34,575
Continuing Operations | Operating Segments | CSS
Segment Reporting Information [Line Items]
Depreciation and amortization									11,781	11,724	12,525
Capital expenditures									15,345	9,600	10,224
Continuing Operations | Corporate
Segment Reporting Information [Line Items]
Depreciation and amortization									2,739	2,384	2,462
Capital expenditures									562	927	141
Continuing Operations | Corporate and eliminations
Segment Reporting Information [Line Items]
Operating income									$ (43,712)	$ (59,079)	$ (40,776)