Fair Value Measurement (Fair Value, Assets Measured on a Recurring Basis, Unobservable Inputs) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Available-for-sale securities, Beginning balance	$ 49,661	$ 49,661	$ 87,539
True-up liability, Beginning balance	12,259	12,259	11,551
Available-for-sale securities, Total unrealized gains/losses		0	0
True-up liability, Total unrealized gains/losses		(796)	708
fair value measurement asssets acquired	3,271
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(2,635)	5,282
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	0
Available-for-sale securities, Purchases		297,231	0
True-up liability, Purchases		0	0
Available-for-sale securities, Sales		0	(40,520)
True-up liability, Sales		0	0
Available-for-sale securities, Settlements		82	(2,640)
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		347,610	49,661
True-up liability, Ending balance		$ 11,463	$ 12,259