Fair Value Measurement (Changes in Level 3 Table) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Available-for-sale securities, Beginning balance	$ 49,661		$ 87,539
True-up liability, Beginning balance	12,259		11,551
Available-for-sale securities, Total unrealized gains/losses	0	[1]	0	[1]
True-up liability, Total unrealized gains/losses	524	[1]	174	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	1,560	[2]	2,419	[2]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	[2]	0	[2]
Available-for-sale securities, Purchases	0		0
True-up liability, Purchases	0		0
Available-for-sale securities, Sales	0		0
True-up liability, Sales	0		0
Available-for-sale securities, Settlements	13		(1,471)
True-up liability, Settlements	0		0
Available-for-sale securities, Transfers	0		0
True-up liability, Transfers	0		0
Available-for-sale securities, Ending balance	51,234		88,487
True-up liability, Ending balance	$ 12,783		$ 11,725

[1] (a) Reported in other expense

[2] (b) Reported in other comprehensive income (loss)