Income Taxes Reconciliation of Unrecognized Income Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 5,661	$ 6,513
Additions based on tax positions related to the current year	5,863	1,298
Additions based on tax positions related to prior years	1,348	395
Reductions for tax positions of prior years	(1,298)	(1,074)
Reductions for expired statute of limitations	(293)	(1,471)
Balance at end of year	$ 11,281	$ 5,661