Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Held-to-maturity, fair value	$ 643,926	$ 609,547
Preferred stock, authorized shares	4,400,000	4,400,000
Common stock, authorized shares	350,000,000	350,000,000
Common stock, issued shares	185,112,965	184,677,696
Common stock, outstanding shares	185,112,965	184,677,696