Condensed Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect Period of Adoption Adjustment	Common Stock	Common Stock Cumulative Effect Period of Adoption Adjustment	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect Period of Adoption Adjustment	Accumulated Earnings (Deficit)	Accumulated Earnings (Deficit) Cumulative Effect Period of Adoption Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect Period of Adoption Adjustment
Balance at Sep. 30, 2019	$ (60,323)	$ (445)	$ 1,167				$ 55,797	$ (445)	$ (117,287)
Balance (in shares) at Sep. 30, 2019			116,725
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201602Member		us-gaap:AccountingStandardsUpdate201602Member		us-gaap:AccountingStandardsUpdate201602Member		us-gaap:AccountingStandardsUpdate201602Member		us-gaap:AccountingStandardsUpdate201602Member
Increase (Decrease) in Stockholders' Equity
Net earnings	53,215						53,215
Other comprehensive income (loss)	14,870								14,870
Repurchases and cancellations of common stock	(11,357)		$ (7)		$ (6,237)		(5,113)
Repurchases and cancellations of common stock (in shares)			(766)
Share-based compensation	3,473				3,473
Stock issued for equity awards	2,766		$ 2		2,764
Stock issued for equity awards (in shares)			206
Balance at Dec. 31, 2019	2,199		$ 1,162				103,454		(102,417)
Balance (in shares) at Dec. 31, 2019			116,165
Balance at Sep. 30, 2019	(60,323)	$ (445)	$ 1,167				55,797	$ (445)	(117,287)
Balance (in shares) at Sep. 30, 2019			116,725
Increase (Decrease) in Stockholders' Equity
Net earnings	66,583
Other comprehensive income (loss)	(6,956)
Balance at Mar. 31, 2020	(53,195)		$ 1,123				69,925		(124,243)
Balance (in shares) at Mar. 31, 2020			112,264
Balance at Dec. 31, 2019	2,199		$ 1,162				103,454		(102,417)
Balance (in shares) at Dec. 31, 2019			116,165
Increase (Decrease) in Stockholders' Equity
Net earnings	13,368						13,368
Other comprehensive income (loss)	(21,826)								(21,826)
Repurchases and cancellations of common stock	(50,000)		$ (39)		(3,064)		(46,897)
Repurchases and cancellations of common stock (in shares)			(3,936)
Share-based compensation	3,059				3,059
Stock issued for equity awards	5				5
Stock issued for equity awards (in shares)			35
Balance at Mar. 31, 2020	(53,195)		$ 1,123				69,925		(124,243)
Balance (in shares) at Mar. 31, 2020			112,264
Balance at Sep. 30, 2020	$ 15,443		$ 1,124		1,913		117,109		(104,703)
Balance (in shares) at Sep. 30, 2020	112,405		112,405
Increase (Decrease) in Stockholders' Equity
Net earnings	$ 57,191						57,191
Other comprehensive income (loss)	23,588								23,588
Share-based compensation	2,893				2,893
Stock issued for equity awards	(249)		$ 1		(250)
Stock issued for equity awards (in shares)			133
Balance at Dec. 31, 2020	98,866		$ 1,125		4,556		174,300		(81,115)
Balance (in shares) at Dec. 31, 2020			112,538
Balance at Sep. 30, 2020	$ 15,443		$ 1,124		1,913		117,109		(104,703)
Balance (in shares) at Sep. 30, 2020	112,405		112,405
Increase (Decrease) in Stockholders' Equity
Net earnings	$ 95,503
Other comprehensive income (loss)	16,272
Balance at Mar. 31, 2021	$ 134,833		$ 1,127		9,525		212,612		(88,431)
Balance (in shares) at Mar. 31, 2021	112,679		112,679
Balance at Dec. 31, 2020	$ 98,866		$ 1,125		4,556		174,300		(81,115)
Balance (in shares) at Dec. 31, 2020			112,538
Increase (Decrease) in Stockholders' Equity
Net earnings	38,312						38,312
Other comprehensive income (loss)	(7,316)								(7,316)
Share-based compensation	2,648				2,648
Stock issued for equity awards	2,323		$ 2		2,321
Stock issued for equity awards (in shares)			141
Balance at Mar. 31, 2021	$ 134,833		$ 1,127		$ 9,525		$ 212,612		$ (88,431)
Balance (in shares) at Mar. 31, 2021	112,679		112,679