Fair Value of Financial Instruments (Fair Value Measurements for Level 3 Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 0	$ 27,177	$ 8,118	$ 26,166
Total realized and unrealized gains (losses):
Included in net income	0	0	0	0
Included in other comprehensive income	0	(1,115)	897	(259)
Purchases, sales, issuances and settlements, net	0	(787)	0	(632)
Transfers into (out of) Level 3	0	0	(9,015)	0
Balance at end of period	0	25,275	0	25,275
Amount of total gains (losses) for the period included in net income attributable to the change in unrealized gains (losses) relating to assets still held at the end of period	0	0	0	0
Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	1,623	3,511	1,647	4,512
Total realized and unrealized gains (losses):
Included in net income	594	(196)	587	(865)
Included in comprehensive income	0	0	0	0
Purchases, sales, issuances and settlements, net	0	(225)	(17)	(557)
Transfers into (out of) Level 3	0	0	0	0
Balance at end of period	2,217	3,090	2,217	3,090
Amount of total gains (losses) for the period included in net income attributable to the change in unrealized gains (losses) relating to assets still held at end of period	621	(196)	651	(865)
Debt Securities, Available for Sale [Member]
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	19,059	0	18,602
Total realized and unrealized gains (losses):
Included in net income	0	0	0	0
Included in other comprehensive income	0	(1,115)	0	(813)
Purchases, sales, issuances and settlements, net	0	(787)	0	(632)
Transfers into (out of) Level 3	0	0	0	0
Balance at end of period	0	17,157	0	17,157
Amount of total gains (losses) for the period included in net income attributable to the change in unrealized gains (losses) relating to assets still held at the end of period	0	0	0	0
Equity Securities, Available for Sale [Member]
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	8,118	8,118	7,564
Total realized and unrealized gains (losses):
Included in net income	0	0		0
Included in other comprehensive income	0	0	897	554
Purchases, sales, issuances and settlements, net	0	0		0
Transfers into (out of) Level 3	0	0	(9,015)	0
Balance at end of period	0	8,118	0	8,118
Amount of total gains (losses) for the period included in net income attributable to the change in unrealized gains (losses) relating to assets still held at the end of period	$ 0	$ 0	$ 0	$ 0

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