Stock Plans (Details) (USD $)	12 Months Ended									12 Months Ended		9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended		12 Months Ended										4 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2011 Price Range 8.19-8.19 [Member]	Dec. 31, 2011 Price Range 10.44-10.44 [Member]	Dec. 31, 2011 Price Range 11.90-14.15 [Member]	Dec. 31, 2011 Price Range 8.19-14.15 [Member]	Dec. 31, 2011 Director [Member]	Dec. 31, 2010 Director [Member]	Dec. 31, 2009 Director [Member]	Dec. 31, 2011 All Employees and Senior Management [Member]	Jul. 02, 2010 All Employees and Senior Management [Member]	Dec. 31, 2010 All Employees [Member]	Dec. 31, 2010 Senior Management [Member]	Sep. 30, 2010 Lead Director [Member]	Dec. 31, 2010 Lead Director [Member]	Sep. 30, 2010 Chair of Audit Committee [Member]	Dec. 31, 2010 Chair of Audit Committee [Member]	Sep. 30, 2010 Chair of Compensations Committee [Member]	Dec. 31, 2010 Chair of Compensations Committee [Member]	Sep. 30, 2010 Chair of Retirement Plan Committee [Member]	Dec. 31, 2010 Chair of Retirement Plan Committee [Member]	Sep. 30, 2010 Chair of Nominating and Corporate Governance Committee [Member]	Dec. 31, 2010 Chair of Nominating and Corporate Governance Committee [Member]	Dec. 31, 2011 All Plans [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2009 Restricted Stock [Member]	Dec. 31, 2011 1996 Equity Incentive Plan [Member]	Dec. 31, 2011 2000 Equity Incentive Plan [Member]	Dec. 31, 2011 2009 Equity Incentive Plans [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2009 Stock Options [Member]	Dec. 31, 2011 Directors' Equity Plan [Member]	Apr. 30, 2004 Directors' Equity Plan [Member] Director [Member]	Sep. 30, 2010 Directors' Equity Plan [Member] Director [Member]	Dec. 31, 2010 Directors' Equity Plan [Member] Director [Member]	Dec. 31, 2009 Directors' Equity Plan [Member] Director [Member]	Dec. 31, 2011 Directors' Equity Plan [Member] Director [Member]	Dec. 31, 2011 EIP [Member]	Dec. 31, 2011 Two plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of stock-based compensation plan																						5
Number of stock-based compensation plans under which no further awards may be granted (the EIP)																						3
Shares available for grant under the plans (in shares)					1,762,724																							5,265,147				540,761
Shares authorized for grant under the plans (in shares)					2,540,761																							10,000,000									2,540,761	12,540,761
Shares available for grant under two plans (in shares)																																							7,027,871
Compensation costs					$ (600,000)	$ 1,700,000	$ 700,000
Cash compensation					700,000	500,000	600,000
Number of shares issued (in shares)																							1,734,000	3,264,000	1,119,000
Stock outstanding (in shares)																							4,847,000									140,616
Compensation expense																							14,800,000	12,800,000	8,700,000
1996, 2000, and 2009 equity incentive plans [Abstract]
Plan expiration dates																										May 22, 2006	May 14, 2009
Expiry period of awards granted (in years)																												10Y						the tenth anniversary of the grant date or the first anniversary of termination of service as a director
Effective date of award																												May 14, 2009
Shares Subject to Option [Roll forward]
Balance at beginning of period (in shares)																													1,507,000	3,551,000	3,713,000
Options granted (in shares)																													0	0	0		5,000		30,000	0
Options exercised (in shares)																													(10,000)	0	(114,000)
Options canceled, forfeited or lapsed (in shares)																													(602,000)	(2,044,000)	(48,000)
Balance at end of period (in shares)																													895,000	1,507,000	3,551,000
Weighted Average Option Price Per Share [Abstract]
Balance at beginning of period (in dollars share)																													$ 10.50	$ 13.74	$ 13.46
Options granted (in dollars per share)																													$ 0	$ 0	$ 0
Options exercised (in dollars per share)																													$ 8.19	$ 0	$ 6.58
Options canceled, forfeited or lapsed (in dollars per share)																													$ 10.86	$ 16.13	$ 9.24
Balance at end of period (in dollars per share)																													$ 9.94	$ 10.50	$ 13.74
Number Outstanding (in shares)	338,000	438,000	119,000	895,000
Range of Exercise Prices, lower limit (in dollars per share)	$ 8.19	$ 10.44	$ 11.90	$ 8.19
Range of Exercise Prices, upper limit (in dollars per share)	$ 8.19	$ 10.44	$ 14.15	$ 14.15
Weighted Average Exercise Price (in dollars per share)	$ 8.19	$ 10.44	$ 13.10	$ 9.94
Weighted Average Remaining Life in Years	0.37	0.69	3.61	1.31
Weighted Average Remaining Life in Years [Abstract]
Balance at beginning of period (in years)																													1.7	1.5	2.5
Balance at end of period (in years)																													1.3	1.7	1.5
Aggregate Intrinsic Value [Abstract]
Balance at beginning of period																													603,000	0	495,000
Options exercised																													12,000		65,000
Balance at end of period																													0	603,000	0
Number of Shares [Roll Forward]
Balance at beginning of period (in shares)																							4,440,000	2,193,000	1,702,000
Restricted stock granted (in shares)								1,911,000															1,734,000	3,264,000	1,119,000
Restricted stock vested (in shares)																							(1,146,000)	(874,000)	(557,000)
Restricted stock forfeited (in shares)																							(181,000)	(143,000)	(71,000)
Balance at end of period (in shares)																							4,847,000	4,440,000	2,193,000
Weighted Average Grant Date Fair Value [Abstract]
Balance at beginning of period (in dollars per shares)																							$ 8.29	$ 10.41	$ 12.52
Restricted stock granted (in dollars per shares)																							$ 9.38	$ 7.54	$ 8.42
Restricted stock vested (in dollars per shares)																							$ 9.52	$ 10.86	$ 12.77
Restricted stock forfeited (in dollars per shares)																							$ 7.99	$ 7.95	$ 11.02
Balance at end of period (in dollars per shares)																							$ 8.40	$ 8.29	$ 10.41
Aggregate Fair Value [Abstract]
Balance at beginning of period																							43,199,000	17,126,000	14,876,000
Restricted stock granted																							8,930,000	31,760,000	8,738,000
Restricted stock vested																							5,899,000	8,507,000	4,347,000
Balance at end of period																							24,962,000	43,199,000	17,126,000
Unvested restricted stock [Abstract]
Restricted stock granted (in shares)								1,911,000															1,734,000	3,264,000	1,119,000
Fair value of restricted stock granted									14,200,000
Number of installments that restricted shares granted will vest											three equal annual installments
Vesting period of stocks granted										the third anniversary of the grant date	one year after the grant date																		4Y
Percentage of stock granted to all employees that vest on the third anniversary of the grant date (in hundredths)										100.00%
Remaining unrecognized compensation cost associated with unvested restricted stock awards																							26,000,000
Weighted average period over which unvested restricted stock awards unrecognized compensation cost is expected to be recognized (in years)																							2
Non-Employee Directors' Compensation Plans [Abstract]
Number of stock options granted to each non-employee director upon commencement of service on the board (in shares)																																		10,000
Effective date of the directors' equity plan																																		2006-05-25
Expiry period of option granted under the plan																												10Y						the tenth anniversary of the grant date or the first anniversary of termination of service as a director
Number of annual stock units granted to each non-employee director (in shares)																																		3,500
Number of stock options award received by each non-employee director (in shares)																													0	0	0		5,000		30,000	0
Percentage of fair market value of option exercise price (in hundredths)																																	100.00%
Exercisable period of stock options granted, minimum (in months)																																	6M	6M
Exercisable period of stock options granted, maximum (in years)																																	10Y
Annual retainer for non-employee directors (option 1, stock units) (in shares)																																		5,760
Annual retainer for non-employee directors (option 2, cash payment)																																		40,000
Fee for each in-person meeting of the board of directors or committee of the board																																		2,000
Fee for each telephonic meeting of the board of directors or committee of the board attended																																		1,000
Annual stipend received by chair of committees												15,000	20,000	25,000	20,000	20,000	20,000	7,500	7,500	7,500	10,000
Annual retainer for non-employee directors in cash																																			75,000
Annual retainer for non-employee directors cash value of stock units																																			75,000
Time period when fees were paid to non-employee directors																																			quarterly
Cash value of the fees payable to the director as a percentage of closing prices of common stock (in hundredths)																																			85.00%
Basis of converting directors stock unit																																			one-to-one
Number of directors participating in the plan during the period																																12
Plan units earned during the period (in shares)																																197,600			95,695	76,326
Options Outstanding [Abstract]
Balance at beginning of period (in dollars share)																													$ 10.50	$ 13.74	$ 13.46
Options granted (in dollars per share)																													$ 0	$ 0	$ 0
Options exercised (in dollars per share)																													$ 8.19	$ 0	$ 6.58
Options canceled, forfeited or lapsed (in dollars per share)																													$ 10.86	$ 16.13	$ 9.24
Balance at end of period (in dollars per share)																													$ 9.94	$ 10.50	$ 13.74
Number Outstanding (in shares)	338,000	438,000	119,000	895,000
Range of Exercise Prices, lower limit (in dollars per share)	$ 8.19	$ 10.44	$ 11.90	$ 8.19
Range of Exercise Prices, upper limit (in dollars per share)	$ 8.19	$ 10.44	$ 14.15	$ 14.15
Weighted Average Exercise Price (in dollars per share)	$ 8.19	$ 10.44	$ 13.10	$ 9.94
Weighted Average Remaining Life in Years	0.37	0.69	3.61	1.31
Options Exercisable [Abstract]
Number Exercisable (in shares)	338,000	438,000	119,000	895,000
Weighted Average Exercise Price (in dollars per share)	$ 8.19	$ 10.44	$ 13.10	$ 9.94
Number of options exercisable at end of period (in shares)																														1,507,000	3,551,000
Weighted average exercise price of exercisable options (in dollars per share)					$ 11.29																									$ 10.50	$ 13.74
Cash received upon exercise of options during the period																													$ 100,000	$ 0	$ 800,000