Stock and Incentive Compensation - Compensation Expense for Awards and Units Under Stock Plan (Details) - Stock and Incentive Compensation Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Compensation expense [Abstract]
Recognized compensation expense	$ 1,116	$ 1,239	$ 4,511	$ 3,907
Performance Awards and Units [Member]
Compensation expense [Abstract]
Recognized compensation expense	311	417	517	(360)
Time-Vested Awards and Units [Member]
Compensation expense [Abstract]
Recognized compensation expense	$ 805	$ 822	$ 3,994	$ 3,547