Employee Benefit and Deferred Compensation Plans - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	274	318	545	636
Expected return on plan assets	(510)	(539)	(1,021)	(1,078)
Prior service cost recognized	0	0	0	0
Recognized actuarial loss	83	46	156	91
Net periodic benefit cost (return)	(153)	(175)	(320)	(351)
Other Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Service cost	4	6	8	12
Interest cost	15	23	30	46
Expected return on plan assets	0	0	0	0
Prior service cost recognized	0	0	0	0
Recognized actuarial loss	26	27	46	54
Net periodic benefit cost (return)	$ 45	$ 56	$ 84	$ 112