Stock-Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Stock option / award activity
Available for future grant (in shares)	3,348,345		3,348,345		3,303,855
Stock options / awards
Stock-based compensation expense	$ 4,500,000	$ 4,700,000	$ 10,100,000	$ 9,200,000
Intrinsic values of stock options exercised	967,000	8,400,000	7,900,000	13,400,000
Stock options
Stock-based compensation
Vesting period			3 years
Stock option / award activity
Options outstanding at the beginning of the period (in shares)			2,326,201	3,419,423	3,419,423
Granted (in shares)			0	0
Exercised (in shares)			(539,733)	(779,394)
Forfeited (in shares)			(15,473)	(60,289)
Options outstanding at the end of the period (in shares)	1,770,995	2,579,740	1,770,995	2,579,740	2,326,201	3,419,423
Available for future grant (in shares)	3,348,345	3,132,053	3,348,345	3,132,053
Total shares reserved at the end of period	5,119,340	5,711,793	5,119,340	5,711,793
Options exercisable at the end of period (in shares)	1,544,332	1,868,765	1,544,332	1,868,765
WEIGHTED-AVERAGE EXERCISE PRICE
Options outstanding at the beginning of the period (in dollars per option)			$ 27.02	$ 26.92	$ 26.92
Granted (in dollars per option)			$ 0.00	$ 0.00
Exercised (in dollars per option)			$ 29.24	$ 25.38
Forfeited (in dollars per option)			$ 21.57	$ 21.24
Options outstanding at the end of the period (in dollars per option)	$ 26.39	$ 27.52	$ 26.39	$ 27.52	$ 27.02	$ 26.92
Options exercisable at the end of period (in dollars per option)	$ 27.49	$ 31.14	$ 27.49	$ 31.14
WEIGHTED-AVERAGE REMAINING CONTRACTUAL LIFE (in years)
Weighted average remaining contractual life, Options outstanding at the end of the period			2 years 4 months 24 days	2 years 8 months 12 days	2 years 3 months 18 days	2 years 10 months 24 days
Weighted average remaining contractual life, Options exercisable at the end of the period			2 years	1 year 10 months 24 days
AGGREGATE INTRINSIC VALUE
Aggregate intrinsic value, Options outstanding at the end of the period	30,216,000	39,960,000	30,216,000	39,960,000
Aggregate intrinsic value, Options exercisable at the end of period	25,571,000	24,266,000	25,571,000	24,266,000
Stock options / awards
Stock-based compensation expense	429,000	965,000	1,100,000	2,100,000
2011 Equity and Incentive Plan
Stock-based compensation
Number of equal annual installments in which awards vest, with performance criteria			3
2011 Equity and Incentive Plan | Senior executive officers
Stock-based compensation
Vesting period			3 years
Number of equal annual installments in which awards vest, with performance criteria			1
2011 Equity and Incentive Plan | Maximum
Stock-based compensation
Expiration period of stock options from date of grant			7 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
Predecessor plans to the 2011 Equity and Incentive Plan | Maximum
Stock-based compensation
Expiration period of stock options from date of grant			10 years
2004 Non-Employee Director Equity 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	189,000	175,000	436,000	385,000
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
Stock option / award activity
Available for future grant (in shares)	117,830		117,830		138,830
Restricted stock units | Senior executive officers
Stock options / awards
Stock-based compensation expense	$ 3,800,000	$ 3,600,000	$ 8,500,000	$ 6,800,000