Employee Benefit Plans (Changes in Fair Value of Plan Assets and Plan Benefit Obligations and Funded Status of Plan) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in Fair Value of Plan Assets
Balance at end of year	$ 75,956	$ 72,617
Employee Pension Plans [Member]
Change in Fair Value of Plan Assets
Balance at beginning of year	72,617	66,137
Actual return on plan assets	3,711	8,545
Company contribution	5,213	3,478
Benefit payments	(5,585)	(5,543)
Balance at end of year	75,956	72,617	66,137
Change in Benefit Obligations
Balance at beginning of year	95,178	105,320
Interest cost	4,144	3,710	4,011
Assumption change loss (gain)	17,054	(9,627)
Actuarial loss	132	1,318
Benefit payments	(5,585)	(5,543)
Balance at end of year	$ 110,923	$ 95,178	$ 105,320