Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Data (Unaudited) [Abstract]
Revenue	$ 1,180,369	$ 1,185,278	$ 1,190,533	$ 1,205,396	$ 1,232,553	$ 1,252,469	$ 1,258,777	$ 1,268,054	$ 4,761,576	$ 5,011,853	$ 5,243,043
Operating income	257,569	206,172	266,156	250,824	235,730	275,196	267,784	208,458	980,721	987,168	899,621
Net income (loss) attributable to common shareholders of Frontier	$ 67,755	$ 35,400	$ (38,460)	$ 48,140	$ 24,879	$ 67,000	$ 17,989	$ 26,768	$ 112,835	$ 136,636	$ 149,614
Basic net income (loss) per common share attributable to common shareholders of Frontier	$ 0.07	$ 0.04	$ (0.04)	$ 0.05	$ 0.02	$ 0.07	$ 0.02	$ 0.03	$ 0.11	$ 0.14	$ 0.15