Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Tower Financial Corporation [Member]	Founders Financial Corporation [Member]	United Bancorp, Inc. [Member]	LSB Financial Corp. [Member]	Common Stock [Member]	Common Stock [Member] Tower Financial Corporation [Member]	Common Stock [Member] Founders Financial Corporation [Member]	Common Stock [Member] United Bancorp, Inc. [Member]	Common Stock [Member] LSB Financial Corp. [Member]	Capital Surplus [Member]	Capital Surplus [Member] Tower Financial Corporation [Member]	Capital Surplus [Member] Founders Financial Corporation [Member]	Capital Surplus [Member] United Bancorp, Inc. [Member]	Capital Surplus [Member] LSB Financial Corp. [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2012	$ 1,194,565					$ 101,179					$ 916,918					$ 146,667	$ 29,801
Net income	100,920															100,920
Other comprehensive income (loss)	(74,267)																(74,267)
Dividends - common stock	(40,278)															(40,278)
Common stock issued	290					22					268
Common stock repurchased	(24,292)					(1,728)					(22,564)
Stock based compensation expense	3,958										3,958
Stock activity under incentive compensation plans	1,744					386					1,674					(316)
Ending Balance at Dec. 31, 2013	1,162,640					99,859					900,254					206,993	(44,466)
Net income	103,667															103,667
Other comprehensive income (loss)	12,911																12,911
Acquisition		$ 78,727		$ 123,806	$ 51,758		$ 5,626		$ 9,117	$ 3,557		$ 73,101		$ 114,689	$ 48,201
Dividends - common stock	(48,181)															(48,181)
Common stock issued	326					24					302
Common stock repurchased	(25,830)					(1,886)					(23,944)
Stock based compensation expense	4,162										4,162
Stock activity under incentive compensation plans	1,778					550					1,527					(299)
Ending Balance at Dec. 31, 2014	1,465,764					116,847					1,118,292					262,180	(31,555)
Net income	116,716															116,716
Other comprehensive income (loss)	(3,242)																(3,242)
Acquisition			$ 50,626					$ 3,402					$ 47,224
Dividends - common stock	(55,552)															(55,552)
Common stock issued	391					29					362
Common stock repurchased	(88,695)					(6,399)					(82,296)
Stock based compensation expense	4,255										4,255
Stock activity under incentive compensation plans	907					418					74					415
Ending Balance at Dec. 31, 2015	$ 1,491,170					$ 114,297					$ 1,087,911					$ 323,759	$ (34,797)