Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense recognized		$ 6,605	$ 5,276	$ 6,108
Unrecognized Compensation Cost		$ 3,400
Expiration date of 2007 Stock Incentive Plan		May 20, 2024
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense recognized		$ 6,396	$ 5,061	$ 5,931
Unrecognized Compensation Cost		$ 3,400
Weighted Average Remaining Amortization Periods		10 months 24 days
Number of units [Abstract]
Balance (in shares)		793,000	842,000	904,000
Granted (in shares)		319,000	272,000	314,000
Vested (in shares)	[1]	(235,000)	(308,000)	(361,000)
Cancelled or forfeited (in shares)		0	(13,000)	(15,000)
Balance (in shares)		877,000	793,000	842,000
Expected to vest (in shares)		877,000	793,000	842,000
Weighted Average Grant-date Fair Value per Unit [Abstract]
Beginning balance, Weighted average grant-date fair value (in dollars per share)		$ 18.90	$ 17.93	$ 14.77
Granted, Weighted average grant-date fair value (in dollars per share)		22.07	18.30	19.85
Vested, Weighted average grant-date fair value (in dollars per share)	[1]	18.79	15.70	11.70
Cancelled or forfeited, Weighted average grant date fair value (in dollars per share)		0	19.06	17.71
Ending balance, Weighted average grant-date fair value (in dollars per share)		$ 20.08	$ 18.90	$ 17.93
Phantom Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense recognized		$ 209	$ 215	$ 177
Unrecognized Compensation Cost		$ 0
Weighted Average Remaining Amortization Periods		0 years
Number of units [Abstract]
Balance (in shares)		198,000	183,000	170,000
Granted (in shares)		10,000	10,000	10,000
Dividend equivalents issued (in shares)		4,000	5,000	3,000
Balance (in shares)		212,000	198,000	183,000
Weighted Average Grant-date Fair Value per Unit [Abstract]
Granted, Weighted average grant-date fair value (in dollars per share)		$ 20.89	$ 21.49	$ 17.72
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2022 [Member]
Number of units [Abstract]
Balance (in shares)	[2]	174,000
Expected to vest (in shares)	[2]	174,000
Not expected to vest (in shares)	[2]	0
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2023 [Member]
Number of units [Abstract]
Balance (in shares)		152,000
Expected to vest (in shares)		152,000
Not expected to vest (in shares)		0
Performance Vested Restricted Stock Units [Member] | Scheduled to Vest January 1, 2024 [Member]
Number of units [Abstract]
Balance (in shares)		165,000
Expected to vest (in shares)		165,000
Not expected to vest (in shares)		0
2007 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Maximum number of shares authorized under restricted stock, unrestricted stock, RSU's and stock options to officers, employees and non-employee directors (in shares)		6,500,000
Exercisable (in shares)
Available for future grants (in shares)		1,975,000

[1] The number of RSUs vested includes shares that the Company withheld on behalf of employees to satisfy statutory tax withholding requirements.

[2] The performance vesting criteria for the performance-based RSUs with a vesting date of January 1, 2022 were achieved.