Employee and Non-Employee Director Stock and Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Number of Shares
Exercised (in shares)			(111,792)
Stock options
Number of Shares
Outstanding at the beginning of the period (in shares)	510,975	526,970	566,963
Granted (in shares)	0		252,464
Exercised (in shares)			(111,792)
Forfeited (in shares)	(167,649)	(15,995)	(180,665)
Outstanding at the end of the period (in shares)	343,326	510,975	526,970
Amount exercisable at the end of the period (in shares)	262,017	319,793	221,344
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 26.77	$ 27.27	$ 32.30
Granted (in dollars per share)			$ 17.16
Exercised (in dollars per share)			$ 1.91
Forfeited (in dollars per share)	$ 46.18	$ 43.15	$ 44.62
Outstanding at the end of the period (in dollars per share)	$ 17.29	$ 26.77	$ 27.27
Amount exercisable at the end of the period (in dollars per share)	$ 17.28	$ 32.53	$ 41.18
2007 Plan
Employee and non-employee director stock and benefit plans
Shares of common stock authorized	10,468,208
2007 Plan | Time-based option awards
Employee and non-employee director stock and benefit plans
Full vesting after the period, on anniversary of the grant	3 years
Directors' Equity Subplan | Restricted stock unit awards
Employee and non-employee director stock and benefit plans
Value of shares granted at or shortly after the time of appointment	$ 100,000
Value of shares granted on the forty fifth day following each of the annual meetings of stockholders	$ 72,000
Vesting period, from first anniversary of grant date	3 years