Stockholders' Equity Stockholders' Equity (Reclassifications out of AOCI into Earnings) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge loss reclassified to interest expense							$ 75,361	$ 70,077	$ 68,846
Cash flow hedge loss reclassified to interest expense, tax	(1,800)	0	[1]	(1,493)	0	[1]	201,121	202,543	178,792
Cash flow hedge loss reclassified to interest expense, net of tax							326	326	326
Interest Rate Lock Commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge loss reclassified to interest expense							517	517	517
Interest Expense, Net [Member] | Interest Rate Lock Commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge loss reclassified to interest expense							517	517	517
Income taxes [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge loss reclassified to interest expense, tax							$ 191	$ 191	$ 191

[1] During the three months ended September 30, 2013, the Company recognized a $1.5 million tax benefit related to a change in a state income tax law, allowing the Company to utilize additional net operating loss carryforwards. During the three months ended March 31, 2014, the Company recognized an additional $1.8 million