Calculated Impairment Charge for Each Market (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impairment Costs [Line Items]
Reporting Unit Fair Value	$ 131,997	$ 131,997
Carrying Value	1,195,594	1,195,594	1,334,512	56,079
Impairment	100,000	100,000
Market 27
Impairment Costs [Line Items]
Reporting Unit Fair Value	49,900	49,900
Implied Goodwill Value	22,488	22,488
Carrying Value	33,452	33,452
Impairment		10,964
Market 60
Impairment Costs [Line Items]
Reporting Unit Fair Value	66,900	66,900
Implied Goodwill Value	34,576	34,576
Carrying Value	54,650	54,650
Impairment		20,074
Market 70
Impairment Costs [Line Items]
Reporting Unit Fair Value	52,900	52,900
Implied Goodwill Value	20,723	20,723
Carrying Value	43,477	43,477
Impairment		22,754
Market 80
Impairment Costs [Line Items]
Reporting Unit Fair Value	126,000	126,000
Implied Goodwill Value	54,210	54,210
Carrying Value	100,418	100,418
Impairment		$ 46,208