Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock-based compensation
Number of shares available for grant	3,016,108	3,346,508
Stock option / award activity
Granted (in shares)	756,000	781,000	846,000
Number of shares available for grant	3,016,108	3,346,508
Stock options / awards
Stock-based compensation expense	$ 17,800	$ 9,700	$ 11,500
Stock options
Stock-based compensation
Number of shares available for grant	3,016,108	3,346,508	1,477,072
Stock option / award activity
Options outstanding at the beginning of the period (in shares)	3,948,874	3,722,656	3,693,697
Granted (in shares)	756,000	781,000	846,000
Exercised (in shares)	(568,293)	(44,398)	(200,758)
Forfeited (in shares)	(717,158)	(510,384)	(616,283)
Options outstanding at the end of the period (in shares)	3,419,423	3,948,874	3,722,656	3,693,697
Number of shares available for grant	3,016,108	3,346,508	1,477,072
Total shares reserved at the end of period	6,435,531	7,295,382	5,199,728
Options exercisable at the end of period (in shares)	1,967,786	2,574,246	2,580,526
WEIGHTED-AVERAGE EXERCISE PRICE
Options outstanding at the beginning of the period (in dollars per option)	$ 28.91	$ 33.29	$ 36.43
Granted (in dollars per option)	$ 18.55	$ 16.52	$ 23.30
Exercised (in dollars per option)	$ 18.89	$ 11.97	$ 8.62
Forfeited (in dollars per option)	$ 35.38	$ 43.36	$ 46.46
Options outstanding at the end of the period (in dollars per option)	$ 26.92	$ 28.91	$ 33.29	$ 36.43
Options exercisable at the end of period (in dollars per option)	$ 33.10	$ 34.35	$ 38.23
WEIGHTED-AVERAGE REMAINING CONTRACTUAL LIFE (in years)
Weighted average remaining contractual life, Options outstanding at the end of the period	2 years 10 months 24 days	2 years 4 months 24 days	2 years 9 months 18 days	3 years 1 month 6 days
Weighted average remaining contractual life, Options exercisable at the end of the period	1 year 7 months 6 days	1 year 8 months 12 days	2 years 3 months 18 days
AGGREGATE INTRINSIC VALUE
Aggregate intrinsic value, Options outstanding at the end of the period	42,992	553	1,315
Aggregate intrinsic value, Options exercisable at the end of period	16,939	369	588
Stock options / awards
Stock-based compensation expense	5,000	4,000	4,700
Intrinsic values of stock options exercised	5,400	284	2,100
2011 Equity and Incentive Plan
Stock-based compensation
Expiration period of stock options from date of grant	7 years
Number of equal annual installments in which awards vest, no performance criteria	3
Predecessor plans to the 2011 Equity and Incentive Plan | Maximum
Stock-based compensation
Expiration period of stock options from date of grant	10 years
Predecessor plans to the 2011 Equity and Incentive Plan | Minimum
Stock-based compensation
Expiration period of stock options from date of grant	5 years
2004 Non-Employee Director Stock Plan and predecessor plans | Maximum
Stock-based compensation
Expiration period of stock options from date of grant	10 years
Non-Employee Director Stock Plans
Stock options / awards
Stock-based compensation expense	404	415	547
2011 Non-Employee Director Stock Plan (the Director Plan)
Stock-based compensation
Number of shares authorized for issuance to each director	3,000
The maximum period of time that can elapse subsequent to a new director's appointment prior to receipt of an initial award in accordance with the plan	30 days
Number of shares available for grant	158,000	176,000
Stock option / award activity
Number of shares available for grant	158,000	176,000
Restricted stock units
Stock-based compensation
Number of equal annual installments in which awards vest, no performance criteria	3
Stock options / awards
Stock-based compensation expense	$ 12,400	$ 5,300	$ 6,300