Share-Based Compensation Plans (Details) (USD $)	12 Months Ended					12 Months Ended										12 Months Ended			12 Months Ended										12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	May 29, 2013	Mar. 21, 2013	Dec. 31, 2013 Restricted stock	Dec. 31, 2013 Common Stock	Dec. 31, 2012 Common Stock	Dec. 31, 2013 Stock Options	Dec. 31, 2012 Stock Options	Dec. 31, 2011 Stock Options	Dec. 31, 2013 97 Plan	Dec. 31, 2013 07 Incentive Plan	Dec. 31, 2011 Amended and restated employment agreement Common Stock	Dec. 31, 2010 Amended and restated employment agreement Common Stock	Dec. 31, 2012 Employee agreement Common Stock	Dec. 31, 2011 Employee agreement Common Stock	Dec. 31, 2010 Employee agreement Common Stock	Dec. 31, 2013 Omnibus Stock Incentive Plans, 2007 New LTIP [Member]	Dec. 31, 2013 Omnibus Stock Incentive Plans, 2007 [Member]	Dec. 31, 2012 Omnibus Stock Incentive Plans, 2007 [Member]	Dec. 31, 2011 Omnibus Stock Incentive Plans, 2007 [Member]	Dec. 31, 2013 04 Plan	Dec. 31, 2010 Previous employment agreement Restricted stock	Dec. 31, 2013 Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2012 Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2011 Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2010 Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2013 Minimum Common Stock	Dec. 31, 2013 Maximum [Member] Common Stock	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	Dec. 31, 2012 Employee Stock Purchase Plan [Member]	Dec. 31, 2011 Employee Stock Purchase Plan [Member]	Dec. 31, 2013 Criteria One Amended and restated employment agreement Restricted stock	Dec. 31, 2012 Criteria One Amended and restated employment agreement Restricted stock	Dec. 31, 2010 Criteria One Amended and restated employment agreement Restricted stock	Dec. 31, 2013 Criteria One Previous employment agreement Restricted stock	Dec. 31, 2012 Criteria One Previous employment agreement Restricted stock	Dec. 31, 2010 Criteria One Previous employment agreement Restricted stock	Dec. 31, 2010 Criteria Two Amended and restated employment agreement Restricted stock	Dec. 31, 2010 Criteria Two Previous employment agreement Restricted stock	Dec. 31, 2010 Criteria Three Previous employment agreement Restricted stock	Dec. 31, 2013 Performance-Based Awards [Member] Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2012 Performance-Based Awards [Member] Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2011 Performance-Based Awards [Member] Churchill 2004 and 2007 Plan [Member] Restricted stock	Dec. 31, 2010 Performance-Based Awards [Member] Churchill 2004 and 2007 Plan [Member] Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 21,482,000	$ 7,613,000	$ 5,531,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	4,900,000					14,900,000
Stock options, contractual term												10 years	10 years	6 years
Award vesting period												3 years	3 years	3 years			3 years			5 years			5 years																	6 years	5 years	5 years
Shares authorized to be purchased	50,000,000	50,000,000													180,000			130,000
Shares exercised									(7,000)	(153,000)	(6,000)					(130,000)
Shares granted (in dollars per share)																$ 36.16
Shares exercised, minimum price																$ 57.36
Shares exercised, maximum price																$ 60.05
Weighted average value of options granted (in dollars per share)
Total intrinsic value of options exercised									300,000	5,700,000	100,000
Cash received from exercised options									300,000	3,400,000	200,000
Shares exercisable at period end										161,000
Shares exercised, weighted average exercise price										$ 36.57
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				155,000	92,000
Minimal age when award becomes fully vested													60 years										60 years
Restricted shares issued to director																																		30,000	15,000	45,000	60,000	52,500	90,000
Restricted shares required before shares become exercisable																																								81,250	65,000	65,000
Options vested in period																									316,000	221,000	70,000																60,000	52,000	0
Consecutive trading days mimimum price per share must be met for options to vest																																				20 days			20 days		10 days
Annual interest rate																								3.00%
Period before options become vested subsequent to termination																								6 months
Recognization of share-based compensation expenses, weighted average period						1 year 11 months																							5 months	29 months
Shares held by Company subject to performance-based vesting criteria																									673,000	379,000	419,000	334,000															324,000	60,000	112,000	112,000
Trading Days	20 days
Employee Stock Purchase Plan [Abstract]
Number of hours required to be considered a full time employee																															20 hours
Number of months per year that an employee needs to work to be considered full-time																															5 months
Percentage of common stock purchase price that employee allowed to purchase at																															85.00%
Maximum stock allowed to be purchased by employee in one year, value																															25,000
Stock sold by company to employees																															17,000
Compensation expense recognized	21,482,000	13,993,000	9,730,000																12,800,000	5,300,000	6,400,000	4,200,000									400,000	400,000	300,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 6,200,000