Net Income Per Common Share (Calculation Of Net Income Per Common Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Income Per Common Share [Abstract]
Net income attributable to common shareholders of Frontier	$ 41,993	$ 35,400	$ 118,947	$ 45,080
Less: Dividends paid on unvested restricted stock awards	(749)	(632)	(2,262)	(1,908)
Total basic and diluted net income attributable to common shareholders of Frontier	$ 41,244	$ 34,768	$ 116,685	$ 43,172
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	1,002,092	999,826	1,001,656	999,017
Less: Weighted average unvested restricted stock awards (in shares)	(7,445)	(6,711)	(7,263)	(6,537)
Total weighted average shares outstanding - basic (in shares)	994,647	993,115	994,393	992,480
Basic net income per share attributable to common shareholders of Frontier	$ 0.04	$ 0.04	$ 0.12	$ 0.04
Effect of dilutive shares (in shares)	3,208	990	3,351	922
Total weighted average shares outstanding - diluted (in shares)	997,855	994,105	997,744	993,402
Diluted net income per common share attributable to common shareholders of Frontier	$ 0.04	$ 0.04	$ 0.12	$ 0.04