Employee Benefits (Schedule of Net Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Qualified Pension Plan [Member]
Change in Benefit Obligation:
Benefit obligation at beginning of period	$ 70,615	$ 57,257
Service cost	2,720	2,574	2,314
Interest cost	2,883	2,823	2,578
Actuarial (gain) loss	(8,809)	9,535
Benefits paid	(2,004)	(1,440)
Administrative expenses	(182)	(134)
Curtailments	(4,061)	0
Benefit obligation at end of period	61,162	70,615	57,257
Change in Plan Assets:
Fair value of plan assets at beginning of period	51,078	38,330
Actual return on plan assets	8,168	4,322
Employer contributions	5,000	10,000
Benefits paid	(2,004)	(1,440)
Administrative expenses	(182)	(134)
Fair value of plan assets at end of period	62,060	51,078	38,330
Funded (unfunded) status at end of period	898	(19,537)
Non-Qualified Retirement Plans [Member]
Change in Benefit Obligation:
Benefit obligation at beginning of period	12,569	11,321
Service cost	181	150	71
Interest cost	462	503	495
Actuarial (gain) loss	(1,332)	1,315
Benefits paid	(736)	(720)
Administrative expenses	0	0
Curtailments	(360)	0
Benefit obligation at end of period	10,784	12,569	11,321
Change in Plan Assets:
Fair value of plan assets at beginning of period	0	0
Actual return on plan assets	0	0
Employer contributions	736	720
Benefits paid	(736)	(720)
Administrative expenses	0	0
Fair value of plan assets at end of period	0	0	0
Funded (unfunded) status at end of period	$ (10,784)	$ (12,569)