Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,778		$ 5,665	$ 8,195		$ 10,976
Change in fair value of derivative instruments:
Change in fair value of derivative instruments for the period	(317)		1,582	(542)		2,020
Income tax effect	111		(554)	190		(707)
Changes from derivative instruments	(206)		1,028	(352)		1,313
Change in securities available-for-sale:
Unrealized appreciation (depreciation) for the period on available-for-sale securities	2,336		(12,168)	6,762		(14,607)
Unrealized appreciation (depreciation) for the period on held-to-maturity	(108)	[1]		(108)	[1]
Reclassification adjustment for securities gains realized in income	0			0		368
Income tax effect	(779)		4,259	(2,329)		4,984
Unrealized gains (losses) on available-for-sale securities	1,449		(7,909)	4,325		(9,255)
Other Comprehensive Income (Loss), Net of Tax	1,243		(6,881)	3,973		(7,942)
Comprehensive Income (Loss)	$ 6,021		$ (1,216)	$ 12,168		$ 3,034

[1] The amortization of the unrealized holding gains in accumulated other comprehensive income at the date of the transfer partially offsets the accretion of the difference between the par value and the fair value of the investment securities at the date of the transfer.