Incentive and Deferred Compensation Plans - Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred executive and outside directors' compensation liability
Total plan awards and earnings	$ 12,566	$ 19,713	$ 18,945
Total plan awards paid	(14,482)	(20,621)	(20,418)
Incentive plan and deferred compensation liabilities at end of period	26,182	30,057	32,908
Annual incentive plan
Deferred executive and outside directors' compensation liability
Annual incentive plan awards	4,751	6,118	6,460
Long-term incentive plan
Deferred executive and outside directors' compensation liability
Long-term incentive plan awards	6,331	10,931	11,321
Forfeitures	0	(593)	(3,117)
Deferred compensation plans and stock compensation plan for outside directors
Deferred executive and outside directors' compensation liability
Employer match and hypothetical earnings on deferred compensation	1,484	2,664	1,164
Compensation deferred	1,928	680	1,214
Distributions from the deferred compensation plans	(1,321)	(853)	(435)
Stock compensation plan for outside directors
Deferred executive and outside directors' compensation liability
Funding of rabbi trust	(1,165)	(1,177)	(738)
Incentive compensation deferral plan
Deferred executive and outside directors' compensation liability
Funding of rabbi trust	$ (1,401)	$ 0	$ 0