Consolidated Statements of Stockholders' Equity and Comprehensive Income (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Preferred Stock	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)
Beginning balance at Dec. 31, 2008	$ 614,892	$ 364,469	$ 121,508	$ 100,184	$ 28,731
Beginning balance, shares at Dec. 31, 2008		83,270
Repurchase of stock	(130,000)		(130,000)
Amortization of preferred stock discount			8,492	(8,492)
Warrant repurchase	(1,307)	(1,307)
Issuance of Common Stock	126,056	126,056
Issuance of Common Stock, Shares		22,655
Exercise of stock options	280	280
Exercise of stock options, Shares		56
Tax benefit from exercise of stock options	62	62
Stock-based Compensation Expense	1,666	1,666
Stock-based Compensation Expense, Shares		282
Cash dividends declared
Common ($0.34 per share)	(32,228)			(32,228)
Preferred	(4,271)			(4,271)
Net earnings	65,419			65,419
Other comprehensive income	(2,341)				(2,341)
Ending balance at Dec. 31, 2009	638,228	491,226		120,612	26,390
Ending balance, shares at Dec. 31, 2009		106,263
Repurchase of stock	(5,169)	(5,169)
Repurchase of common stock		(640)
Exercise of stock options	1,547	1,547
Exercise of stock options, Shares		304
Tax benefit from exercise of stock options	425	425
Stock-based Compensation Expense	2,197	2,197
Stock-based Compensation Expense, Shares		149
Cash dividends declared
Common ($0.34 per share)	(36,103)			(36,103)
Net earnings	62,935			62,935
Other comprehensive income	(20,205)				(20,205)
Ending balance at Dec. 31, 2010	643,855	490,226		147,444	6,185
Ending balance, shares at Dec. 31, 2010		106,076
Repurchase of stock	(12,527)	(12,527)
Repurchase of common stock		(1,595)
Exercise of stock options	59	59
Exercise of stock options, Shares	9	9
Tax benefit from exercise of stock options	1	1
Stock-based Compensation Expense	2,214	2,214
Stock-based Compensation Expense, Shares		(8)
Cash dividends declared
Common ($0.34 per share)	(35,805)			(35,805)
Net earnings	81,733			81,733
Other comprehensive income	35,284				35,284
Ending balance at Dec. 31, 2011	$ 714,814	$ 479,973	$ 0	$ 193,372	$ 41,469
Ending balance, shares at Dec. 31, 2011		104,482