Employee Benefits Plans (Gain (Loss) NQDC Plan Investment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Gross realized gains from sale of trading securities	$ 2,639	$ 1,530	$ 823
Gross realized losses from sale of trading securities	0	(5)	0
Dividend and interest income	876	1,483	808
Net unrealized holding gains (losses)	7,090	4,047	(3,595)
(Gain) loss on deferred compensation plan securities	$ 10,605	$ 7,055	$ (1,964)