Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 31,537	$ 25,577	$ 61,551	$ 49,434
Other comprehensive income (loss):
Change in unrealized gains on securities	(1,723)	553	(839)	1,341
Increase (decrease) in fair value of cash flow hedge	3,635	(2,079)	1,305	(3,137)
Less: reclassification adjustment for amounts recognized in net income	(1,177)	(1,190)	(2,134)	(1,718)
Total other comprehensive income (loss)	735	(2,716)	(1,668)	(3,514)
Comprehensive income	32,272	22,861	59,883	45,920
Less: comprehensive income attributable to noncontrolling interest	(355)	(283)	(685)	(606)
Comprehensive income attributable to common stockholders	$ 31,917	$ 22,578	$ 59,198	$ 45,314