Stockholders' Equity and Equity Compensation Plans (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Aug. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2014
Stockholders Equity And Equity Compensation Plans [Line Items]
Accrued excise tax	$ 900		$ 900		$ 900
Remaining number of shares available for repurchase	100,000	100,000	100,000		100,000
Remaining authorized repurchase amount		$ 100,000
Repurchase of common stock for employee tax withholdings, shares			3,000	7,000	171,000	132,000
Repurchase of common stock for tax withholdings, value			$ 100	$ 400	$ 9,600	$ 8,400
Cash dividends declared per common share			$ 0.28	$ 0.265
Cash dividend			$ 8,700	$ 8,400	$ 26,400	25,400
Stock warrants term							10 years
Stock warrants, exercise price							$ 26.68
Performance based awards granted to executive management and certain key employees shares					134,000
Vesting maturity date					first quarter of 2025
Vesting period					2 years
Stock-based compensation expense			$ 7,200	$ 8,700	$ 21,253	$ 20,778
Market-based Awards
Stockholders Equity And Equity Compensation Plans [Line Items]
Awards vested					45,000
Restricted common stock
Stockholders Equity And Equity Compensation Plans [Line Items]
Awards vested			9,000		480,000
Restricted common stock | Minimum
Stockholders Equity And Equity Compensation Plans [Line Items]
Vesting period					2 years
Restricted common stock | Maximum
Stockholders Equity And Equity Compensation Plans [Line Items]
Vesting period					3 years
Comcast
Stockholders Equity And Equity Compensation Plans [Line Items]
Issuance of stock warrants							2,900,000
Stock warrants issued	1,000,000		1,000,000		1,000,000
Stock warrants vested					0
SEC Rule 10b5-1 Plan
Stockholders Equity And Equity Compensation Plans [Line Items]
Repurchase of common stock, shares		275,000	1,991,000	488,000	1,991,000	1,114,000
Total amount paid		$ 15,000	$ 107,000	$ 27,900	$ 107,000	$ 65,500
Weighted-average price per share		$ 54.65	$ 53.73	$ 57.27	$ 53.73	$ 58.8
2023 Convertible Notes
Stockholders Equity And Equity Compensation Plans [Line Items]
Repurchase of common stock, shares	1,680,000
Total amount paid	$ 90,100
Weighted-average price per share	$ 53.62
Second SEC Rule 10b5-1 Plan
Stockholders Equity And Equity Compensation Plans [Line Items]
Repurchase of common stock, shares	36,000
Total amount paid	$ 1,900
Weighted-average price per share	$ 52.13
Remaining authorized repurchase amount	$ 100,000		$ 100,000		$ 100,000
2005 Stock Incentive Plan
Stockholders Equity And Equity Compensation Plans [Line Items]
Increase in number of common stock shares authorized and reserved for issuance		2,900,000
Number of common stock shares authorized and reserved for issuance		27,900,000