Stock-Based Compensation - Stock Compensation Plans (Details) - $ / shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Stock Options Outstanding
Stock options outstanding, number of shares, balance (in shares)	658,000
Stock options granted (in shares)	0	0
Stock options exercised, exercised (in shares)	(183,000)
Stock options forfeited/expired (in shares)	0
Stock options outstanding, number of shares, balance (in shares)	475,000
Stock options outstanding, number of shares, exercisable (in shares)	475,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Stock options, weighted average exercise price, balance (in dollars per share)	$ 22.48
Stock options, weighted average exercise price, granted (in dollars per share)	0
Stock options, weighted average exercise price, exercised (in dollars per share)	22.50
Stock options, weighted average exercise price, forfeited/expired (in dollars per share)	0
Stock options, weighted average exercise price, balance (in dollars per share)	22.47
Stock options outstanding, weighted average exercise price, exercisable (in dollars per share)	$ 22.47
Non-vested Stock Awards Outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested shares outstanding, balance (in shares)	5,000
Non-vested shares outstanding, granted (in shares)	0
Non-vested shares outstanding, vested (earned) (in shares)	(3,000)
Non-vested shares outstanding, forfeited/expired (in shares)	0
Non-vested shares outstanding, balance (in shares)	2,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share)	$ 22.35
Non-vested shares outstanding. weighted-average grant-date fair value, granted (in dollars per share)	0
Non-vested shares outstanding. weighted-average grant-date fair value, vested (earned) (in dollars per share)	22.48
Non-vested shares outstanding. weighted-average grant-date fair value, forfeited/expired (in dollars per share)	0
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share)	$ 22.20
Non-vested Stock Units Outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested shares outstanding, balance (in shares)	1,032,000
Non-vested shares outstanding, granted (in shares)	526,000
Non-vested shares outstanding, vested (earned) (in shares)	(331,000)
Non-vested shares outstanding, forfeited/expired (in shares)	(77,000)
Non-vested shares outstanding, balance (in shares)	1,150,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share)	$ 24.53
Non-vested shares outstanding. weighted-average grant-date fair value, granted (in dollars per share)	29.00
Non-vested shares outstanding. weighted-average grant-date fair value, vested (earned) (in dollars per share)	25.62
Non-vested shares outstanding. weighted-average grant-date fair value, forfeited/expired (in dollars per share)	25.78
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share)	$ 26.14