Net Income Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net income used for basic and diluted earnings per common share [Abstract]
Net income attributable to common shareholders of Frontier	$ 48,140	$ 26,768
Less: Dividends paid on unvested restricted stock awards	(521)	(737)
Total basic and diluted net income attributable to common shareholders of Frontier	$ 47,619	$ 26,031
Basic earnings per common share [Abstract]
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	998,146,000	995,897,000
Less: Weighted average unvested restricted stock awards (in shares)	(6,273,000)	(7,024,000)
Total weighted average shares outstanding - basic (in shares)	991,873,000	988,873,000
Net income per share attributable to common shareholders of Frontier (in dollars per share)	$ 0.05	$ 0.03
Diluted earnings per common share [Abstract]
Effect of dilutive shares (in shares)	675,000	12,000
Effect of dilutive stock units (in shares)	0	623,000
Total weighted average shares outstanding - diluted (in shares)	992,548,000	989,508,000
Net income per share attributable to common shareholders of Frontier (in dollars per share)	$ 0.05	$ 0.03
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)	526,000	895,000
Exercise price range of stock options related to employee compensation plans - lower range limit (in dollars per share)	$ 10.44	$ 8.19
Exercise price range of stock options related to employee compensation plans - upper range limit (in dollars per share)	$ 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)	949,412	623,121