Employee Benefits (Components of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (on a pre-tax basis):
Recognized in other comprehensive income	$ (20,406)	[1]	$ 8,445	[1]	$ 10,502	[1]
Qualified Pension Plan [Member]
Net Periodic Benefit Cost:
Service cost	2,720		2,574		2,314
Interest cost	2,883		2,823		2,578
Expected return on plan assets	(3,725)		(2,985)		(2,794)
Amortization of prior service (credit) cost	(30)		(33)		(33)
Recognized net actuarial loss	1,321		982		392
Curtailments	(61)		0		0
Net periodic benefit cost	3,108		3,361		2,457
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (on a pre-tax basis):
Net loss (gain)	(14,572)		7,216		8,951
Prior service cost (credit)	30		33		33
Curtailment	(4,000)		0		0
Recognized in other comprehensive income	(18,542)		7,249		8,984
Total recognized in net periodic benefit cost and other comprehensive income	(15,434)		10,610		11,441
Non-Qualified Retirement Plans [Member]
Net Periodic Benefit Cost:
Service cost	181		150		71
Interest cost	462		503		495
Expected return on plan assets	0		0		0
Amortization of prior service (credit) cost	(1)		(1)		(1)
Recognized net actuarial loss	175		119		16
Curtailments	(1)		0		0
Net periodic benefit cost	816		771		581
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (on a pre-tax basis):
Net loss (gain)	(1,506)		1,195		1,517
Prior service cost (credit)	1		1		1
Curtailment	(359)		0		0
Recognized in other comprehensive income	(1,864)		1,196		1,518
Total recognized in net periodic benefit cost and other comprehensive income	$ (1,048)		$ 1,967		$ 2,099

[1] Included in salaries and employee benefits expense in the Consolidated Statements of Income.