Employee Benefits - Benefit Obligation and Plan Assets Deriving Funded Status, in Other Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	$ 109,747	$ 113,124
Service cost	463	2,601	$ 2,369
Interest cost	4,296	4,425	4,470
Actuarial loss (gain)	3,575	(4,257)
Curtailments	(6,997)	0
Benefits paid	(5,250)	(6,146)
Projected Benefit Obligation at End of Year	105,834	109,747	113,124
Change in Plan Assets
Fair value of plan assets at beginning of year	84,585	93,486
Actual return on plan assets	8,376	(2,755)
Benefits paid	(5,250)	(6,146)
Fair Value of Plan Assets at End of Year	87,711	84,585	$ 93,486
Funded Status	$ (18,123)	$ (25,162)