Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Treasury stock, shares of common stock (in shares)	1,447,594	2,420,800	1,810,383
Retirement of treasury shares (in shares)	(1,447,594)	(2,420,800)	(1,810,383)
Interest rate swap, tax	$ 653	$ 194	$ (660)
Exercise and lapse of share-based awards, tax benefit	$ 7,706	$ 5,524	$ 4,611