Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Business Acquisition [Line Items]
Goodwill	$ 803,487	$ 791,468
Future amortization expense associated with the acquired intangibles for fiscal year ended September 30, 2023	24,862
Future amortization expense associated with the acquired intangibles for fiscal year ended September 30, 2024	28,195
Future amortization expense associated with the acquired intangibles for fiscal year ended September 30, 2025	28,185
Future amortization expense associated with the acquired intangibles for fiscal year ended September 30, 2026	28,137
Future amortization expense associated with the acquired intangibles for fiscal year ended September 30, 2027	$ 27,536