Condensed Financial Information (Parent Company Only) - Condensed Balance Sheets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed balance sheets:
Cash and cash equivalents	$ 534,827	$ 801,332
Investment in subsidiaries, at equity:
Other assets	61,056	62,953
Total assets	7,564,651	7,721,761
Preferred stock pending redemption	0	50,000
Subordinated debentures held by subsidiary trusts	82,477	82,477
Total liabilities	6,763,070	6,970,575
Stockholders’ equity	801,581	751,186	771,020	736,802
Total liabilities and stockholders’ equity	7,564,651	7,721,761
Parent Company
Condensed balance sheets:
Cash and cash equivalents	105,274	95,407
Investment in subsidiaries, at equity:
Equity method investments	795,872	804,239
Advances from subsidiaries, net	0	697
Other assets	26,809	25,815
Total assets	927,955	926,158
Other liabilities	17,602	22,495
Advances to subsidiaries, net	6,295	0
Long-term debt	20,000	20,000
Preferred stock pending redemption	0	50,000
Subordinated debentures held by subsidiary trusts	82,477	82,477
Total liabilities	126,374	174,972
Stockholders’ equity	801,581	751,186
Total liabilities and stockholders’ equity	927,955	926,158
Bank subsidiary
Investment in subsidiaries, at equity:
Equity method investments	793,892	802,270
Nonbank subsidiaries
Investment in subsidiaries, at equity:
Equity method investments	$ 1,980	$ 1,969