Stock-Based Compensation Stock-Based Compensation - Stock Option and Restricted Stock Unit Activity (Details) - $ / shares		3 Months Ended
		Mar. 31, 2018		Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	[1]	8,820,888	[2]	9,227,890
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	[1],[3]	$ 10.44		$ 10.36
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		378,016
Restricted stock units and awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	[4]	14,121,592	[2]	17,274,659
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	[3],[4]	$ 12.04		$ 11.22
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		114,136
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period		3,042,607

[1] During the three months ended March 31, 2018, 378,016 stock options were exercised.

[2] Granted 114,136 restricted stock units related to CEC common stock during the three months ended March 31, 2018. No stock options granted during the three months ended March 31, 2018.

[3] Represents weighted average exercise price for stock options and weighted average fair value for restricted stock units.

[4] During the three months ended March 31, 2018, 3,042,607 restricted stock units vested.