Net Income (Loss) Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net income used for basic and diluted earnings per common share [Abstract]
Net income (loss) attributable to common shareholders of Frontier	$ (38,460)	$ 17,989	$ 9,680	$ 44,757
Less: Dividends paid on unvested restricted stock awards	(755)	(735)	(1,276)	(1,472)
Total basic and diluted net income (loss) attributable to common shareholders of Frontier	$ (39,215)	$ 17,254	$ 8,404	$ 43,285
Basic earnings per common share [Abstract]
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	999,234,000	998,462,000	998,770,000	996,989,000
Less: Weighted average unvested restricted stock awards (in shares)	(6,623,000)	(7,279,000)	(6,606,000)	(7,120,000)
Total weighted average shares outstanding - basic (in shares)	992,611,000	991,183,000	992,164,000	989,869,000
Net income (loss) per share attributable to common shareholders of Frontier (in dollars per share)	$ (0.04)	$ 0.02	$ 0.01	$ 0.04
Diluted earnings per common share [Abstract]
Effect of dilutive shares (in shares)	603,000	0	449,000	10,000
Effect of dilutive stock units (in shares)	0	0	0	704,000
Total weighted average shares outstanding - diluted (in shares)	993,214,000	991,183,000	992,613,000	990,583,000
Net income (loss) per share attributable to common shareholders of Frontier (in dollars per share)	$ (0.04)	$ 0.02	$ 0.01	$ 0.04
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings per share (in shares)	93,000	557,000	93,000	557,000
Exercise price range of stock options related to employee compensation plans - lower range limit (in dollars per share)	$ 12.50	$ 8.19	$ 12.50	$ 8.19
Exercise price range of stock options related to employee compensation plans - upper range limit (in dollars per share)	$ 14.15	$ 14.15	$ 14.15	$ 14.15
Non-Employee Directors' Deferred Fee Plan and Equity Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings per share (in shares)	1,044,128	704,527	1,044,128	704,527