Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of cash flows specific transaction amounts [Abstract]
Income taxes paid		$ 16,321	$ 13,710	$ 14,520
Interest expense paid on deposits and borrowings		20,733	22,268	25,715
Noncash transfers from loans to foreclosed properties	[1]	$ 32,782	39,778	41,042
Transfer of long-term FHLB advances to short-term			6,644	0
Assets acquired in business combination			0	1,845,543
Liabilities assumed in business combination			$ 0	$ 1,821,066

[1] (1) Includes transfers from covered loans to foreclosed properties.