Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Data (Unaudited) [Abstract]
Revenue	$ 1,232,553,000	$ 1,252,469,000	$ 1,258,777,000	$ 1,268,054,000	$ 1,283,152,000	$ 1,290,939,000	$ 1,322,255,000	$ 1,346,697,000	$ 5,011,853,000	$ 5,243,043,000	$ 3,797,675,000
Operating income	235,730,000	275,196,000	267,784,000	208,458,000	230,457,000	180,291,000	238,280,000	250,593,000	987,168,000	899,621,000	771,998,000
Net income attributable to common shareholders of Frontier	24,879,000	67,000,000	17,989,000	26,768,000	42,247,000	20,395,000	32,261,000	54,711,000	136,636,000	149,614,000	152,673,000
Basic net income per share attributable to common shareholders of Frontier (in dollars per share)	$ 0.02	$ 0.07	$ 0.02	$ 0.03	$ 0.04	$ 0.02	$ 0.03	$ 0.05	$ 0.14	$ 0.15	$ 0.23
Acquisition and integration costs	13,500,000	4,500,000	28,600,000	35,100,000	42,200,000	67,400,000	20,300,000	13,200,000	81,737,000	143,146,000	137,142,000
Severance costs, before tax	17,200,000	6,800,000	1,500,000	6,500,000	1,100,000	3,600,000	11,000,000	100,000
Acquisition and integration costs, after tax	9,100,000	2,900,000	18,100,000	21,700,000	26,100,000	41,600,000	12,600,000	8,200,000
Severance costs, after tax	$ 11,500,000	$ 4,500,000	$ 900,000	$ 4,000,000	$ 700,000	$ 2,200,000	$ 6,800,000	$ 100,000
Acquisition and integration costs, after tax effect on net income (in dollars per share)	$ 0.01	$ 0.00	$ 0.02	$ 0.02	$ 0.03	$ 0.04	$ 0.01	$ 0.01
Severance costs, after tax effect on net income (in dollars per share)	$ 0.01	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.01	$ 0.00