Net Income Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income used for basic and diluted earnings per common share [Abstract]
Net income attributable to common shareholders of Frontier	$ 17,989	$ 32,261	$ 44,757	$ 86,972
Less: Dividends paid on unvested restricted stock awards	(735)	(955)	(1,472)	(1,921)
Total basic and diluted net income attributable to common shareholders of Frontier	$ 17,254	$ 31,306	$ 43,285	$ 85,051
Basic earnings per common share [Abstract]
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	998,462,000	994,482,000	996,989,000	994,413,000
Less: Weighted average unvested restricted stock awards (in shares)	(7,279,000)	(5,125,000)	(7,120,000)	(4,933,000)
Total weighted average shares outstanding - basic (in shares)	991,183,000	989,357,000	989,869,000	989,480,000
Net income per share attributable to common shareholders of Frontier (in dollars per share)	$ 0.02	$ 0.03	$ 0.04	$ 0.09
Diluted earnings per common share [Abstract]
Total weighted average shares outstanding - basic (in shares)	991,183,000	989,357,000	989,869,000	989,480,000
Effect of dilutive shares (in shares)	0	805,000	10,000	1,446,000
Effect of dilutive stock units (in shares)	0	0	704,000	442,000
Total weighted average shares outstanding - diluted (in shares)	991,183,000	990,162,000	990,583,000	991,368,000
Net income per share attributable to common shareholders of Frontier (in dollars per share)	$ 0.02	$ 0.03	$ 0.04	$ 0.09
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)	557,000		577,000
Exercise price range of stock options related to employee compensation plans - lower range limit (in dollars per share)	$ 8.19		$ 9.52
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)			704,527	442,212