Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 23,856	$ 15,923
Other comprehensive income (loss):
Change in unrealized gains on securities	787	1,961
Less: reclassification adjustment for gains in net income	0	0
Increase (decrease) in fair value of cash flow hedge	(1,056)	399
Less: reclassification adjustment for amounts recognized in net income	(528)	(129)
Total other comprehensive income (loss)	(797)	2,231
Comprehensive income	23,059	18,154
Less: comprehensive income attributable to noncontrolling interest	323	180
Net Income (Loss) Attributable to Noncontrolling Interest	323	180
Comprehensive income attributable to common stockholders	$ 22,736	$ 17,974