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Share-Based Compensation and Cash-Based Incentive Compensation - Additional Information (Details) (USD $)
In Millions, except Share data, unless otherwise specified |
9 Months Ended | 12 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 9 Months Ended | 12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Sep. 30, 2014
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Sep. 30, 2014
Common Stock
|
Sep. 30, 2014
Restricted Stock Units (RSUs)
|
Sep. 30, 2013
Restricted Stock Units (RSUs)
|
Dec. 31, 2013
Restricted Stock Units (RSUs)
|
Dec. 31, 2012
Restricted Stock Units (RSUs)
|
Dec. 31, 2013
Restricted Stock Units (RSUs)
London Interbank Offered Rate (LIBOR)
|
Dec. 31, 2012
Restricted Stock Units (RSUs)
London Interbank Offered Rate (LIBOR)
|
Mar. 31, 2014
CEO's 2013 Award
|
Sep. 30, 2014
Directors Compensation Plan
|
Sep. 30, 2014
Restricted Stock
|
Sep. 30, 2013
Restricted Stock
|
Sep. 30, 2014
Minimum
Restricted Stock Units (RSUs)
|
Dec. 31, 2013
Minimum
Restricted Stock Units (RSUs)
|
Dec. 31, 2012
Minimum
Restricted Stock Units (RSUs)
|
Sep. 30, 2014
Maximum
Restricted Stock Units (RSUs)
|
Dec. 31, 2013
Maximum
Restricted Stock Units (RSUs)
|
Dec. 31, 2012
Maximum
Restricted Stock Units (RSUs)
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||||||||
| Restricted stock units adjustments, percentage | 0.00% | 100.00% | ||||||||||||||||
| Common stock, price per share | $ 14.66 | |||||||||||||||||
| Common stock available for award under plans | 5,032,939 | 500,564 | ||||||||||||||||
| Shares granted, grant date fair value | $ 20.0 | $ 12.8 | $ 0.3 | $ 0.3 | ||||||||||||||
| Shares vested, vested date fair value | 0.1 | 0 | 0.3 | 0.4 | ||||||||||||||
| Risk-free interest rate, minimum | 0.27% | 0.15% | ||||||||||||||||
| Risk-free interest rate, maximum | 0.91% | 0.72% | ||||||||||||||||
| Expected volatility, minimum | 30.00% | 33.00% | ||||||||||||||||
| Expected volatility, maximum | 63.00% | 74.00% | ||||||||||||||||
| Expected dividend yield | 0.00% | 0.00% | 3.10% | 2.50% | ||||||||||||||
| Correlation of movement of total shareholder return | (84.00%) | (67.00%) | 95.00% | 94.00% | ||||||||||||||
| Number of shares granted | 1,190,920 | 42,547 | 18,815 | |||||||||||||||
| Number of shares issued | 42,547 | |||||||||||||||||
| Unrecognized share-based compensation expense | $ 0.2 | $ 21.7 | $ 0.6 | |||||||||||||||
| Recognition period for unrecognized compensation expense | 2015-02 | 2016-11 | 2016-04 | |||||||||||||||